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LlBRABYoftbe
OHIO STATE

UNIVERSITY

Vol. I.

Hand' of Bme different Mammals . s-ontevj-

" aeCke5 i Man, 2. Gorilla, 3. Orcmx, , 4.I>og 5 Seal
'6. Porpoise, 7. Bat, 8. MoU, 9. DiuJc-bill.

THE

HISTOEY OP CEEATION

OR THE DEVELOPMENT OF THE EARTH AND ITS
INHABITANTS BY THE ACTION OF NATURAL CAUSES

A POPULAR EXPOSITION OF

THE DOCTRINE OF EVOLUTION IN GENERAL, AND OF THAT OF

DAEWIN, GOETHE, AND LAMARCK IN PARTICULAR

FROM THE EIGHTH GERMAN EDITION OP

ERNST HAECKEL

PROFESSOR IN THE UNIVERSITY OF JENA

THE TRANSLATION REVISED BY

E. BAY LANKESTEE, M.A., LL.D., E.R.S.

LINACRE PROFESSOR OP HUMAN AND COMPARATIVE ANATOMY IN THE UNIVERSITY OP OXFORD
FELLOW OF MERTON COLLEGE, AND HONORARY FELLOW OF EXETER COLLEGE

IN TWO VOLUMES.— Vol. I.

FOURTH EDITION

NEW YORK

D. APPLETON & CO.

1892

A sense sublime
Of something far more deeply interfused,
Whose dwelling is the light of setting suns,
And the round ocean, and the living air,
And the blue sky, and in the mind of man ;
A motion and a spirit that impels
All thinking things, all objects of all thought,
And rolls through all things.

In all things, in all natures, in the stars
Of azure heaven, the unenduring clouds,
In flower and tree, in every pebbly stone
That paves the brooks, the stationary rooks,
The moving waters and the invisible air.

WOEDSWORTH.

CONTENTS OF VOL. I.

CHAPTER I.

NATURE AND IMPORTANCE OF THE DOCTRINE OF
FILIATION, OR DESCENT THEORY. .

FAGS

General Importance and Essential Nature of the Theory of Descent
as reformed by Darwin. — Its Special Importance to Biology
(Zoology and Botany). — Its Special Importance to the History
of the Natural Development of the Human Race. — The Theory
of Descent as the Non-Miraculous History of Creation. — Idea of
Creation. — Knowledge and Belief. — History of Creation and His.
tory of Development. — The Connection between the History of
Individual and Palaaontological Development. — The Theory of
Purposelessness, or the Science of Rudimentary Organs. — Useless
and Superfluous Arrangements in Organisms. — Contrast between
the two entirely opposed Views of Nature : the Monistic (me-
chanical, causal) and the Dualistic (teleological, vital). — Proof of
the former by the Theory of Descent. — Unity of Organic and
Inorganic Nature, and the Identity of the Active Causes in both.
— The Absolute Importance of the Theory of Descent to the Monistic
Conception of all Nature ... 1

CHAPTER II.

SCIENTIFIC JUSTIFICATION OF THE THEORY OF DESCENT.
HISTORY OF CREATION ACCORDING TO LINNJEUS.

The Theory of Descent, or Doctrine of Filiation, as the Monistic Expla-
nation of Organic Natural Phenomena. — Its Comparison with
Newton's Theory of Gravitation. — Limits of Scie ,u±nc Explanation

VI CONTENTS.

and of Human Knowledge in general. — All Knowledge founded
originally on Sensuous Experience, a posteriori. — Transition of a
posteriori Knowledge, by Inheritance, into a priori Knowledge. —
Contrast between the Supernatural Hypotheses of the Creation
according to Linnaeus, Cuvier, Agassiz, and the Natural Theories
of Development according to Lamarck, Goethe, and Darwin. —
Connection of the former with the Monistic (mechanical), of the
latter with the Dualistic Conception of the Universe. — Monism
and Materialism. — Scientific and Moral Materialism. — The History
of Creation according to Moses. — Linnaeus as the Founder of the
Systematic Description of Nature and Distinction of Species. —
Linnaeus' Classification and Binary Nomenclature. — Meaning of
Linnaeus' Idea of Species. — His History of Creation. — Linnseus'
View of the Origin of Species .. . ... ... ... 25

CHAPTEE III.

THE HISTORY OF CREATION ACCORDING TO CUVIER
AND AGASSIZ.

General Theoretical Meaning of the Idea of Species. — Distinction
between the Theoretical and Practical Definition of the Idea of
Species. — Cuvier's Definition of Species. — Merits of Cuvier as the
Founder of Comparative Anatomy. — Distinction of the Four
Principal Forms (types or branches) of the Animal Kingdom, by
Cuvier and Bar. — Cuvier's Services to Palaeontology. — His Hypo-
thesis of the Revolutions of our Globe, and the Epochs of Creation
separated by them. — Unknown Supernatural Causes of the Revo-
lutions, and the subsequent New Creations. — Agassiz's Teleological
System of Nature. — His Conception of the Plan of Creation, and
its six Categories (groups in classification). — Agassiz's Views of
the Creation of Species. — Rude Conception of the Creator as a
man-like being in Agassiz's Hypothesis of Creation. — Its internal
Inconsistency and Contradictions with the important Palseonto-
logical Laws discovered by Agassiz ... ... ... 49

CHAPTEE IV.

THEORY OF DEVELOPMENT ACCORDING TO GOETHE
AND OKEN.

CONTENTS. vi

PAGE

— Greek Philosophy. — The Meaning of Natural Philosophy. —
Goethe. — His Merits as a Naturalist. — His Metamorphosis of
Plants. — His Vertebral Theory of the Skull. — His Discovery of the
Mid Jawbone in Man. — Goethe's Interest in the Dispute between
Cuvier and Geoffroy St. Hilaire. — Goethe's Discovery of the Two
Organic Formative Principles, of the Conservative Principle of
Specification (by Inheritance), and of the Progressive Principle
of Transformation (by Adaptation). — Goethe's Views of the
Common Descent of all Vertebrate Animals, including Man. —
Theory of Development according to Gottfried Eeinhold Trevi-
ranus. — His Monistic Conception of Nature. — Oken. — His Natural
Philosophy. — Oken's Theory of Protoplasm.— Oken's Theory of
Infusoria (Cell Theory) ... ... ... ... ... ... 74

CHAPTER V.

THEORY OP DEVELOPMENT ACCORDING TO KANT
AND LAMARCK.

Kant's Services to the Theory of Development.— His Monistic Cosmo-
logy and Dualistic Biology. — Contradiction between the Mechanical
and Teleological Conception. — Comparison of Genealogical Biology
with Comparative Philology. — Views in favour of the Theory of
Descent entertained by Leopold Buch, Bar, Schleiden, Unger,
Schaaffhansen, Victor Cams, Biichner. — FrenchNature-Philosophy.
Lamarck's Pbilosophie Zoologique. — Lamarck's Monistic (me-
chanical) System of Nature. — His Views of the Interaction of the
Two Organic Formative Tendencies of Inheritance and Adaptation.
— Lamarck's Conception of Man's Development from Ape-like
Mammals. — Geoffroy St. Hilaire's, Naudin's, and Lecoq's Defence
of the Theory of Descent. — -English Nature-Philosophy. — Views in
favour of the Theory of Descent, entertained by Erasmus Darwin,
"W. Herbert, Grant, Freke, Herbert Spencer, Hooker, Huxley. —
The Double Merit of Charles Darwin ... ... ... ... 102

CHAPTER VI.

THEORY OF DEVELOPMENT ACCORDING TO LYELL
AND DARWIN.

Charles Lyell's Principles of Geology. — His Natural History of the
Earth's Development. — Origin of the Greatest Effects through
the Multiplication of the Smallest Causes. — Unlimited Extent of
Geological Periods. — Lyell's Refutation of Cuvier's History of

VlU CONTENTS.

PAGE

Creation. — The Establishment of the Uninterrupted Connection
of Historical Development by Lyell and Darwin. — Biographical
Notice of Charles Darwin. — His Scientific Works. — His Theory of
Coral Beefs. — Development of the Theory of Selection. — A Letter
of Darwin's. — The Contemporaneous Appearance of Darwin's and
Alfred Wallace's Theory of Selection. — Darwin's Study of Domestic
Animals and Cultivated Blants. — Andreas Wagner's notions as to
the Special Creation of Cultivated Organisms for the Good of Man.
— The Tree of Knowledge in Paradise. — Comparison between Wild
and Cultivated Organisms. — Darwin's Study of Domestic Pigeons.
— Importance of Pigeon-breeding. — Common Descent of all Baces
of Pigeons 128

CHAPTEE VII.

THE THEORY OP SELECTION (DARWINISM).

Darwinism (Theory of Selection) and Lamarckism (Theory of Descent).
— The Process of Artificial Breeding. — Selection of the Different
Individuals for After.breeding. — The Active Causes of Transmuta-
tion. — Change connected with Pood, and Transmission by Inheritance
connected with Propagation. — Mechanical Nature of these Two
Physiological Functions. — The Process of Natural Breeding :
Selection in the Struggle for Existence. — Malthns' Theory of
Population. — The Proportion between the Numbers of Potential
and Actual Individuals of every Species of Organisms. — General
Struggle for Existence, or Competition tp attain the Necessaries
of Life. — Transforming Force of the Struggle for Existence. —
Comparison of Natural and Artificial Breeding. — Selection in the
Life of Man. — Medical and Clerical Selection .... ... ... 153

CHAPTEE VIII.

TRANSMISSION BY INHERITANCE AND PROPAGATION.

CONTENTS. ix

PAGE

formation of Germ-Buds, by the formation of Germ-Cells. — Sexual
or Amphigonous Propagation. — Formation of Hermaphrodites. —
Distinction of Sexes, or Gonoohorism. — Tirginal Breeding, or
Parthenogenesis. — Material Transmission of Peculiarities of both
Parents to the Child b j Sexual Propagation ... 180

CHAPTER IX.

LAWS OP TRANSMISSION BY INHERITANCE.

Theories of Inheritance. — Difference between Transmission by Inheri-
tance in Sexual and Non-sexual Propagation. — Distinction between
Conservative and Progressive Transmission by Inheritance. — Laws
of Conservative Transmission : Transmission of Inherited Characters.
— Uninterrupted or Continuous Transmission. — Interrupted or
Latent Transmission. — Alteration of Generations. — Relapse. —
Degeneracy. — Sexual Transmission. — Secondary Sexual Characters.
— Mixed or Amphigonous Transmission. — Hybrids. — Abridged or
Simplified Transmission. — Laws of Progressive Inheritance :
Transmission of Acquired Characters. — Adapted or Acquired
Transmission. — Pixed or Established Transmission. — Homochronous
Transmission (Identity in time) . — Homotopic Transmission (Identity
in place). — Molecular Theories of Transmission. — Pangenesis
(Darwin). — Perigenesis (Haeckel). — Idioplasma (Nageli). — Germ-
plasma (Weismann). — Intracellular Pangenesis (Tries) ... ... 204

CHAPTER X.

ADAPTATION AND NUTRITION. LAWS OF ADAPTATION.

Adaptation and Variation. — Connection between Adaptation and
Nutrition (Change of Matter and Growth). — Distinction between
Indirect and Direct Adaptation. — Laws of Indirect or Potential
Adaptation. — Individual Adaptation. — Monstrous or Sudden
Adaptation. — Sexual Adaptation. — Laws of Direct or Actual
Adaptation. — Universal Adaptation. — Cumulative Adaptation. —
Cumulative Influence of External Conditions of Existence and
Cumulative Counter-influence of the Organism. — Free-will. — Use
and Non-Use of Organs. — Practice and Habit. — Functional Adapta-
tion. — Correlative Adaptation. — Correlation of Development. —
Correlation of Organs. — Explanation of Indirect or Potential
Adaptation by the Correlation of the Sexual Organs and of the
other Parts of the Body. — Aping or Mimetic Adaptation (Mimicry).
— Divergent Adaptation. — Unlimited or Infinite Adaptation ... 238
VOL. I. b

X CONTENTS.

CHAPTBE XI.

NATURAL SELECTION BY THE STRUGGLE FOR EXISTENCE.
CELLULAR SELECTION AND PERSONAL SELECTION.

PAGE

Interaction of the Two Organic Formative Causes, Inheritance and
Adaptation.— Natural and Artificial Selection. — Struggle for
Existence, or Competition for the Necessaries of Life. — Dispropor-
tion between the Number of Possible or Potential, and the Number
of Real or Actual Individuals. — Complicated Correlations of all
Neighbouring Organisms. — Mode of Action in Natural Selection. —
Homoohromic Selection as the Cause of Sympathetic Colourings.
— Sexual Selection as the Cause of the Secondary Sexual Characters.
— The Struggle of Parts in the Organism (Roux). — Functional
Self-Formation of Suitable Structures. — Teleological Mechanism. —
Cellular Selection (Protista) and Personal Selection (Histonas). —
Selection of the Cells and of the Tissues. — The Principle of Selection
in Empedocles. — Mechanical Origin of what is Suitable for a Pur-
pose from what is Unsuitable. — Philosophical Range of Darwinism 273

CHAPTEE XII.

DIVISION OF LABOUR AND DIVERGENCE OF FORMS. PROGRESS
AND RETROGRADATION.

Division of Labour (Ergonomy) and Divergence of Forms (Polymor-
phism). — Physiological Divergence and Morphological Differentia-
tion both necessarily determined by Selection. — Transition of
Varieties into Species. — The Idea of Species. — Hybridism — Per-
sonal Divergence and Cellular Divergence. — Differentiation of the
Tissues.— Primary and SecondaryTissues. — Siphonophora. — Change
of Labour (Metergy).' — Convergence. — The Law of Progress and
Perfectioning. — The Laws of the Development of Mankind. — The
Relation between Progress and Divergence. — Centralization as
Progress. — Retrogradation. — The Origin of Rudimentary Organs by
Non-Use and Habits discontinued. — The Doctrine of Purposeless-
ness, or Dysteleology 300

CHAPTBE XIII.

THE INDIVIDUAL DEVELOPMENT OF ORGANISMS. THE HISTORT
OF THE DEVELOPMENT OF THE ANIMAL TRIBES.

General Importance of Individual Development (Ontogeny). — Defects
of our Present Education. — Facts in the Individual Development.
— Agreement in the Individual Development of Man and the

CONTENTS. xi

PAGE

Tertebrate Animals. — The Human Egg. — Fertilization. — Immor-
tality. — The Cleavage of the Egg. — Formation of Germ-layers. —
Gastrulation. — History of the Development of the Central Nervous
System, of the Extremities, of the Branchial Arches and of the
Tail in Vertebrate Animals. — Causal Connection between Onto-
genesis and Phylogenesis. — The Fundamental Law of Biogenesis.
— Palingenesis or Recapitulative Development. — Cenogenesis or
Disordered Development. — Stages in Comparative Anatomy. — Its
Relation to the Palasontological and Embryological Series of
Development 332

CHAPTER XIV.

MIGRATION AND DISTRIBUTION OF ORGANISMS. CHOROLOGY
AND THE ICE PERIOD OF THE EARTH.

Chorological Facts and Causes. — Origin of most Species in one Single
Locality : " Centres of Creation." — Distribution by Migration.—
Active and Passive Migrations of Animals and Plants. — Flying
Animals. — Analogies between Birds and Insects. — Bats. — Means
of Transport. — Transport of Germs by Water and by Wind. — Con-
tinual Change of the Area of Distribution by Elevations and
Depressions of the Gronnd. — Chorological Importance of Geological
Processes. — Influence of the Change of Climate. — Ice or Glacial
Period. — Its Importance to Chorology. — Importance of Migrations
for the Origin of New Species. — Isolation of Colonists. — Wagner's
Law of Migration. — Connection between the Theory of Migration
and the Theory of Selection. — Agreement of its Results with the
Theory of Descent 363

CHAPTER XV.

THEORY OF THE DEVELOPMENT OF THE UNIVERSE AND
OF THE EARTH. SPONTANEOUS GENERATION. THE
' CARBON THEORY. THE PLASTID THEORY.

History of the Development of the Earth. — Kant's Theory of the De-
velopment of the Universe, or the Cosmological Gas Theory. —
Development of Suns, Planets, and Moons. — First Origin of Water.
— Comparison of Organisms and Anorgana. — Organic and Inor-
ganic Substances. — Degrees of Density, or Conditions of Aggre-
gation. — Albuminous Combinations of Carbon. — Plasson-bodies. —
Organic and Inorganic Forms. — Crystals and Monera. — Formless
Organisms without Organs.— Stereometrical Fundamental Forms

xll CONTENTS.

PA OB

of Crystals and of Organisms. — Organic and Inorganic Forces. —
Vital Force. — Growth and Adaptation in Crystals and in Organisms.
— Formative Tendencies of Crystals. — Unity of Organic and In-
organic Nature. — Spontaneous Generation, or Archigony. — Auto-
gony and Plasmogony. — Origin of Monera by Spontaneous Genera-
tion. — Origin of Cells from Monera. — The Cell Theory. — The
Plastid Theory. — Hastids or Structural- Units. — Cytods and Cells.
—Four Different Kinds of Plastids 390

LIST OF ILLUSTRATIONS.

PLATES.

IV. — Hand of Nine different Mammals ...
I. — Life History of a Simplest Organism

' >Germs or Embryos of Four Vertebrates

V. — Development of the Gastrula

PAGE

... Frontispiece
To face page 188

Between pp. 334, 335

To face page 344

FIGURES.

1. — Propagation of Moneron

2.— Propagation of Amoeba

3. — Egg of Mammal

4. — First Development of Mammal's Egg

5.— The Human Egg Enlarged

6. — Development of Mammal's Egg
7. — Embryo of a Mammal or Bird...

191
193
194

195
339
343
349

AUTHORS PREFACE TO THE ENGLISH EDITION,

I AM desirous of prefacing the English edition of the
" History of Creation " with a few remarks which may serve
to explain the origin and object of this hook. In the year
1866 I published, under the title " Generelle Morphologie,"
a somewhat comprehensive work, which constituted the first
attempt to apply the general doctrine of development to the
whole range of organic morphology (Anatomy and Biogenesis),
and thus to make use of the vast march onwards which the
genius of Charles Darwin has effected in all biological
science by his reform of the Descent Theory and its esta-
blishment through the doctrine of selection. At the same
time, in the " Generelle Morphologie," the first attempt was
made to introduce the Descent Theory into the systematic
classification of animals and plants, and to found a " natural
system " on the basis of genealogy ; that is, to construct
hypothetical pedigrees for the various species of organisms.

The " Generelle Morphologie " found but few readers, for
which the voluminous and unpopular style of treatment, and
its too extensive Greek terminology, may be chiefly to blame.
But a proportionately large measure of approval has met

XVI' PREFACE.

the " Naturliche Schbpfungsgeschichte " in Germany. This
book took its origin in the shorthand notes of a course of
lectures which treated, before a mixed audience and in
a popular form, the most important topics discussed in the
"Generelle Morphologie." The notes were subsequently
revised, and received considerable additions. The book
appeared first in 1868, its fourth edition in 1873, and has
been translated into several languages. I hope that it may
also find sympathy in the fatherland of Darwin, the more so
since it contains special morphological evidence in favour of
many of the important doctrines with which this greatest
naturalist of our century has enriched science. Proud as
England may be to be called the fatherland of Newton, who,
with his law of gravitation, brought inorganie nature under
the dominion of natural laws of cause and effect, yet may
she with even greater pride reckon Charles Darwin among
her sons — he who solved the yet harder problem of bring-
ing the complicated phenomena of organic nature under the
sway of the same natural laws.

The reproach which is now oftenest made against the
Descent Theory is that it is not securely founded, not suffi-
ciently proven. Not only its distinct opponents maintain that
there is a want of satisfactory proofs, but even faint-hearted
and wavering adherents declare that Darwin's hypothesis is
still wanting fundamental proof. Neither the former nor the
latter estimate rightly the immeasurable weight which the
great series of phenomena of comparative anatomy and onto-
geny, palaeontology and taxonomy, chorology and cecology,
cast into the scale in favour of the doctrine of filiation.
Darwin's Theory of Selection, which completely explains the
origin of species through the combined action of Inheritance

PREFACE. xvii

and Adaptation in the struggle for existence, also appears to
these persons not sufficient. They demand, over and ahove,
that the descent of species from common ancestral forms
shall be proved in a particular case; that, in contradistinc-
tion to the synthetic proofs adduced for the Descent Theory,
the analytic proof of the genealogical continuity of the
several species shall be brought forward.

This " analytical solution of the problem of the origin of
species " I have myself endeavoured to afford in my recently
published " Monograph of the Calcareous Sponges." For five
consecutive years I have investigated this small but highly
instructive group of animals in all its forms in the most
careful manner, and I venture to maintain that the mono-
graph, which is the result of those studies, is the most
complete and accurate morphological analysis of an entire
organic group which has up to this time been made.
Provided with the whole of the material for study as yet
brought together, and assisted by numerous contributions
from all parts of the world, I was able to work over the
whole group of organic forms known as the Calcareous
Sponges in that greatest possible degree of fulness which
appeared indispensable for the proof of the common origin
of its species. This particular animal group is especially
fitted for the analytical solution of the species problem,
because it presents exceedingly simple conditions of organ-
ization, because in it the morphological conditions possess a
greatly superior, and the physiological conditions an inferior,
import, and because all species of Calcispongise are remark-
able for the fluidity and plasticity of their form. With a
view to these facts, I made two journeys to the sea-coast
(1869 to Norway, 1871 to Dalmatia), in order to study as

XVlll PREFACE.

large a number of individuals as possible in their natural
circumstances, and to collect specimens for comparison. Of
many species, I compared several hundred individuals in the
most careful way. I examined with the microscope and
measured in the most accurate manner the details of form of
all the species. As the final result of these exhaustive
and almost endless examinations and measurements it
appeared that "good species/' in the ordinary dogmatic
sense of the systematists, have no existence at all among
the Calcareous Sponges ; that the most different forms are
connected one with another by numberless gradational
transition forms ; and that all the different species of Calca-
reous Sponges are derived from a single exceedingly simple
ancestral form, the Olynthus. A drawing of the Olynthus
and its earliest stages of development (observe especially the
highly important Gastrula) is given in the frontispiece of
the present edition. Illustrations of the various structural
details which establish the derivation of all Calcareous
Sponges from the Olynthus, are given in the atlas of
sixty plates which accompanies my monograph of the
group. In the gastrula, moreover, is now also found the
common ancestral form from which all the tribes of animals
(the lowest group, that of the protozoa, alone being excepted)
can without difficulty be derived. It is one of the most
ancient and important ancestors of the human race !

If we take for the limitation of genus and species an average
standard, derived from the actual practice of systematists, and
apply this to the whole of the Calcareous Sponges at present
known, we can distinguish about twenty-one genera, with one
hundred and eleven species (as I have done in the second
volume of the Monograph). I have, however, shown that we

PREFACE. xix

may draw up, in addition to this, another systematic arrange-
ment (more nearlyagreeing with the arrangement of the Calci-
spongige hitherto. in vogue) which gives thirty-nine genera
and two hundred and eighty-nine species. A systematist
who gives a more limited extension to the " ideal species "
might arrange the same series of forms in forty-three genera
and three hundred and eighty-one species, or even in one
hundred and thirteen genera and five hundred and ninety
species ; another systematist, on the other hand, who takes a
wider limit for the abstract " species," would use in arrang-
ing the same series of forms only three genera, with twenty-
one species, or might even satisfy himself with one genua
and seven species. The delimitation of species and genera
appears to be so arbitrary a matter, on account of endless
varieties and transitional forms in this group, that their
number is entirely left to the subjective taste of the indi-
vidual systematist. In truth, from the point of view of the
theory of descent, it appears altogether an unimportant ques-
tion as to whether we give a wider or a narrower signifi-
cation to allied groups of forms — whether we choose, that is
to say, to call them genera or species, varieties or sub-species.
The main fact remains undeniable, viz., the common origin
of all the species from one ancestral form. The many-
shaped Calcareous Sponges furnish, in the very remarkable
conditions of their varieties of aggregation (metrocormy), a
body of evidence in favour of this view which could hardly
be more convincing. Not unfrequently the case occurs of
several different forms growing out from a single " stock "
or " cormus " — forms which until now have been regarded
by systematists, not only as belonging to different species,
but even to different genera. Fig. 10 in the frontispiece

xx PREFACE.

represents such a composite stock. This solid and tangible
piece of evidence in favour of the common descent oi
different species ought, one would think, to satisfy the most
determined sceptic !

In point of fact, I have a right to expect of my opponents
that they shall carefully consider the " exact empirical proof"
here brought forward for them, as they have so eagerly
demanded. The opponents of the doctrine of filiation, who
have too little power of weighing evidence, or possess too
little knowledge to appreciate the overpowering weight of
proof afforded by the synthetical argument (comparative
anatomy, ontogeny, taxonomy, etc.), may yet be able to
follow me along the path of analytical proof, and attempt to
upset the conclusion as to the common origin of all species
of all Calcareous Sponges which I have given in my Mono-
graph. I must, however, repeat that this conclusion is
based on the most minute investigation of an extraordinarily
rich mass of material, — that it is securely established by
thousands of the most careful microscopical observations,
measurements, and comparisons of every single part, and
that thousands of collected microscopic preparations render,
at any moment, the most searching criticism of my results
confirmatory of their correctness. One may hope, then, that
opponents will endeavour to confront me on the ground of
this "exact empiricism," instead of trying to damn my
"nature-philosophical speculations." One may hope that
they will endeavour to bring forward some evidence to
show that the latter do not follow as the legitimate conse-
quences of the former. May they, however, spare me the
empty — though by even respectable naturalists oft-repeated
— phrase, that the monistic nature-philosophy, as expounded

PREFACE. xxi

in the "General Morphology," and in the "History of
Creation," is wanting in actual proofs. The proofs are
there. Of course those who turn their eyes away from
them will not see them. Precisely that "exact" form of
analytical proof which the opponents of the descent theory
demand is to be found, by anybody who wishes to find it,
in the " Monograph of the Calcareous Sponges."

Eenst Heinkioh Haeckel.

Jena, June 24th, 1873.

EDITOR'S PREFACE TO THE NEW ENGLISH
EDITION.

The " History of Creation " has been so much modified by
its author, Professor Haeckel, in its successive German
editions, and so much new matter introduced, that it was
felt to be desirable that a new English edition of the work
should be prepared. The translation of the new matter,
which amounts to nearly half of the whole work, has been
made by Miss Schmitz from the eighth German edition,
published in 1889, and revised by me. The new portions
of the work have been necessitated by the progress of
knowledge since the appearance of the first English trans-
lation in 1876. They comprise an account of recent.
theories which have grown out of Darwin's great doctrine,
and of many new results of investigations, such as those
made by the naturalists of the Challenger Expedition, and
others who, like Professor Haeckel himself, have taken
part in describing the rich stores of zoological specimens
brought home by H.M.S. Challenger.

The book in its present form cannot fail to interest all
who have a taste for natural history. It may be safely
trusted as an introduction to the study of modern biology,
provided that the reader will remember that there are

XXIV PEEFACB.

matters of opinion and theory concerning which many
naturalists do not hold quite the same views as those
adopted by Professor Haeckel. He himself is careful to
draw the reader's attention to the fact that many of his
" pedigrees " and other suggestions are only provisional. I
feel it due to myself to state that I do not agree with him
as to a very large part of his views on classification, and
as to his belief in the necessity of assuming the " trans-
missibility of acquired characters." Readers who have
gained an interest in these questions from the brief state-
ments of the present work must, without assuming that
Professor Haeckel's judgment is final, go on to study for
themselves the works of Weismann and others, which are
mentioned with perfect fairness in these pages.

No work of the scope of the "History of Creation"
could possibly satisfy every critic. It is a sufficient
recommendation for it that it is the statement of the views
of one of the most learned, experienced, and honoured
naturalists of modern times, whose original monographs on
Radiolaria, Sponges, and Jelly-fishes have been of immense
importance to the progress of science, and have excited
the admiration of his brother-naturalists throughout the
world by the beauty of the innumerable drawings with
which he has illustrated them, and by the extraordinary
insight with which he has explained in their pages the
most complicated structures.

E. Ray Lankestek.

Oxford, February, 1892.

THE HISTOEY OF CREATION.

CHAPTER I.

NATURE AND IMPORTANCE OP THE DOCTRINE OP
FILIATION, OR DESCENT THEORY.

General Importance and Essential Nature of the Theory of Descent as re-
formed by Darwin. — Its Special Importance to Biology (Zoology and
Botany) . — Its Special Importance to the History of the Natural Develop-
ment of the Human Bace. — The Theory of Descent as the Non-Miraculous
History of Creation. — Idea of Creation. — Knowledge and Belief. — His-
tory of Creation and History of Development. — The Connection between
the History of Individual and Palseontological Development.- — The
Theory of Purposelessness, or the Science of Rudimentary Organs. —
Useless and Superfluous Arrangements in Organisms. — Contrast between
the two entirely opposed Tiews of Nature : the Monistic (mechanical,
causal) and the Dualistic (teleological, vital). — Proof of the former by
the Theory of Descent. — -Unity of Organic and Inorganic Nature, and
the Identity of the Active Causes in both. — The Absolute Importance
of the Theory of Descent to the Monistic Conception of all Nature.

The intellectual movement to -which the impulse was given
thirty years ago, by the English naturalist, Charles Darwin
in his celebrated work, " On the Origin of Species," * has,
within this short period, assumed dimensions of unparalleled
depth and breadth. It is true the scientific theory set forth
in that work, which is commonly called briefly Darwinism,
is only a small fragment of a far more comprehensive
doctrine — a part of the universal Theory of Development,

VOL. I. B

2 THE HISTORY OF CREATION.

which embraces in its vast range the whole domain of
human knowledge.

But the manner in which Darwin has firmly established
the latter by the former is so convincing, and the direction
which has been given by the unavoidable conclusions of
that theory to all our views of the universe, must appear to
every thinking man of such deep significance, that its
general importance cannot be over-estimated. There is no
doubt that this immense extension of our intellectual
horizon must be looked upon as by far the most important,
and rich in results, among all the numerous and grand
advances which natural science has made in our day.

When our century, with justice, is called the age of
natural science, when we look with pride upon the im-
mensely important progress made in all its branches, we
are generally in the habit of thinking more of immediate
practical results, and less of the extension of our general
knowledge of nature. We call to mind the complete
reform, so infinitely rich in consequences to human inter-
course, which has been' effected by the development of
machinery, by railways, steamships, telegraphs, and other
inventions of physics. Or we think of the enormous in-
fluence which chemistry has brought to bear upon medicine,
agriculture, and upon all arts and trades.

But much as we may value this influence of modern
science upon practical life, still it must, estimated from a
higher and more general point of view, stand most assuredly
below the enormous influence which the theoretical progress
of modern science will have on the entire range of human
knowledge, on our conception of the universe, and on the
perfecting of man's culture.

IMPORTANCE OF DARWINISM. 3

Think of the immense revolutions in all our theoretical
views which we owe to the general application of the
microscope. Think of the cell theory, which explains the
apparent unity of the human organism as the combined
result of the union of a mass of elementary living units.
Or consider the immense extension of our theoretical
horizon which we owe to spectral analysis and to the
mechanical theory of heat. But among all these wonderful
theoretical advances, the theory wrought out by Darwin
occupies by far the highest rank.

Every one of my readers has heard of the name of Dar-
win. But most persons have probably only an imperfect
idea of the real value of his theory. For if all that has
been written upon Darwin's memorable work since its
appearance be equally trusted, the value of the theory must
appear very doubtful to those who have not been engaged
in the organic natural sciences, and have not penetrated
into the inner secrets of zoology and botany. The criticisms
of it are so full of contradictions, and for the most part so
defective, that we ought not to be at all astonished that
even now, after the lapse of thirty years since the appear-
ance of Darwin's work, it has not gained half that im-
portance which is justly due to it, and which sooner or later
it certainly will attain.

Most of the innumerable writings which have been pub-
lished during these years, both for and against Darwinism,
are the productions of persons who are entirely wanting in
the necessary amount of biological, and especially of zoolo-
gical, knowledge. Although almost all of the more celebrated
naturalists of the present day are now adherents of the
theory, yet only a few of them have endeavoured to procure

4 THE HISTORY OF CREATION.

its acceptance and recognition in larger circles. Hence the
odd contradictions and the strange opinions which are still
on every side heard about Darwinism. This is the reason
which induces me to make Darwin's theory, and those
further doctrines which are connected with it, the subject
of these pages, which, I hope, will be generally intelligible.
I hold it to be the duty o£ naturalists, not merely to medi-
tate upon improvements and discoveries in the narrow circle
to which their speciality confines them, not merely to pore
over their one study with love and care, but also to seek to
make the important general results of it fruitful to the mass,
and to assist in spreading the knowledge of physical science
among the people. The highest triumph of the human
mind, the true knowledge of the most general laws of
nature, ought not to remain the private possession o£ a
privileged class of learned men, but ought to become the
common property of all mankind.

The thebry which, through Darwin, has been placed at
the head of all our knowledge of nature, is usually called
the Doctrine of Filiation, or the Theory of Descent. Others
term it the Transmutation Theory. Both designations are
correct. For this doctrine affirms, that all organisms (viz.
all species of animals, all species of plants, which have ever
existed or still exist on the earth) are derived from one
single, or from a few simple original forms, and that they
have slowly developed from these by a natural course of
gradual change. Although this theory of development had
already been bi - ought forward and defended by several
great naturalists, and especially by Lamarck and Goethe, in
the beginning of our century, still it was through Darwin,
in 1859, that it received its complete demonstration and

OBGANA AND ANOKGANA. 5

causal foundation; and this is the reason why now it is
commonly and exclusively (though not quite correctly)
designated as Darwin's Theory.

The inestimable value of the Theory of Descent appears
in a different light, accordingly as we consider its more
immediate connection with organic natural science, or its
larger influence upon the whole range of man's knowledge
of the universe. Organic natural science, or Biology, which
as Zoology treats of animals, as Botany of plants, is com-
pletely reformed and founded anew by the Theory of
Descent. For by this theory we are made acquainted with
the active causes of organic forms, while up to the present
time Zoology and Botany have simply been occupied
with the facts of these forms. We may therefore also
term the theory of descent a mechanical explanation of
organic forms, or the science of the true causes of Organic
Nature.

As I cannot take for granted that my readers are all
familiar with the terms "organic and inorganic nature,"
and as the contrast of both these natural bodies will, in
future, occupy much of our attention, I must say a few
words in explanation of them. We designate as Organisms,
or Organic bodies, all living creatures or animated bodies ;
therefore all plants and animals, man included ; for in them
we can almost always prove a combination of various parts
(instruments or organs) which work together for the purpose
of producing the phenomena of life. Such a combination
we do not find in Anorgana, or inorganic natural bodies—
the so-called dead or inanimate bodies, such as minerals or
stones, water, the atmospheric air, etc. Organisms always
contain albuminous combinations of carbon in a semi-fluid

6 THE HISTORY OF CREATION.

condition of aggregation, which are always wanting in the
Anorgana. Upon this important distinction rests the divi-
sion of all natural history into two great and principal parts
— Biology, or the science of Organisms (Anthropology,
Zoology, and Botany), and Anorganology, or the science o£
Anorgana (Mineralogy, Geology, Meteorology, etc.).

The immense value of the Theory of Descent in regard to
Biology consists, as I have already remarked, in its explain-
ing to us the origin of organic forms in a mechanical way,
and pointing out their active causes. But however highly
and justly this service of the Theory of Descent may be
valued, yet it is almost eclipsed by the immense importance
which a single necessary inference from it claims for itself
alone. This necessary and unavoidable inference is the
theory of the animal descent of the human race.

The determination of the position of man in nature, and
of his relations to the totality of things — this question of all
questions for mankind, as Huxley justly calls it — is finally
solved by the knowledge that man is descended from
animals. As a consequence of the Theory of Descent or
Transmutation, we are now in a position to establish
scientifically the groundwork of a non-miraculous history of
the development of the human race. All those who have
defended Darwin's theory, as well as all its thoughtful
opponents, have acknowledged that, as a matter of necessity,
it follows from his theory that the human race, in the first
place, must be traced to ape-like mammals, and further back
to the lower vertebrate animals.

It is true Darwin himself did not express at first this
most important of all the inferences from his theory. In
his work, " On the Origin of Species," not a word is found

OEIGIN OF MAN. 7

about the animal descent of man. The courageous but
cautious naturalist was at that time purposely silent on the
subject, for he anticipated that this most important of all
the conclusions of the Theory of Descent was at the same
time the greatest obstacle to its being generally accepted
and acknowledged. Certain it is that Darwin's book would
have created, from the beginning, even much more opposi-
tion and offence, if this most important inference had at
once been clearly expressed. It was not till twelve years
later, in his work on " The Descent of Man, and Selection
in Relation to Sex," that Darwin openly acknowledged that
far-reaching conclusion, and expressly declared his entire
agreement with those naturalists who had, in the mean time,
themselves formed that conclusion. Manifestly the effect of
this conclusion is immense, and no science will be able to
escape from the consequences. Anthropology, or the science
of man, and consequently all philosophy, are thereby
thoroughly reformed in all their various branches.

It will be a later task in these pages to discuss this
special point. I shall not treat of the theory of the animal
descent of man till I have spoken of Darwin's theory, and
its general foundation and importance. To express it in
one word, that most important, but (to most men) at first
repulsive, conclusion is nothing more than a special deduc-
tion, which we must draw from the general inductive law
of the descent theory (now firmly established), according to
the stern commands of inexorable logic.

Perhaps nothing will make the full meaning of the theory
of descent clearer than calling it "the non-miraculous
history of creation." It is, however, correct only in a
certain sense, and it must be borne in mind that, strictly

8 THE HISTORY OF CEEATION.

speaking, the expression " non-miraculous history of crea-
tion " contains a " contradictio in adjecto."

In order to understand this, let us for a moment examine
somewhat more closely what we understand by creation.
If we understand the creation to mean the coming into
existence of a body by a creative power or force, we may
then either think of the coming into existence of its sub-
stance (corporeal matter), or of the coming into existence of
its form (the corporeal form).

Creation in the former sense, as the coming into existence
of matter, does not concern us here at all. This process, if
indeed it ever took place, is completely beyond human com-
prehension, and can therefore never become a subject of
scientific inquiry. Natural science teaches that matter is
eternal and imperishable, for experience has never shown
us that even the smallest particle of matter has come into
existence or passed away. Where a natural body seems to
disappear, as for example by burning, decaying, evaporation,
etc., it merely changes its form, its physical composition or
chemical combination. In like manner the coming into
existence of a natural body, for example, of a crystal, a
fungus, an infusorium, depends merely upon the different
particles, which had before existed in a certain form or com-
bination, assuming a new form or combination in conse-
quence of changed conditions of existence. But never yet
has an instance been observed of even the smallest particle
of matter having vanished, or even of an atom being added
to the already existing mass. Hence a naturalist can no
more imagine the coming into existence of matter, than he
can imagine its disappearance, and he therefore looks upon
the existing quantity of matter in the universe as a given

SCIENCE AND FAITH. Q

fact. If any person feels the necessity of conceiving the
coming into existence of this matter as the work of a super-
natural creative power, of the creative force of something
outside of matter, we have nothing to say against it. But
we must remark, that thereby not even the smallest advan-
tage is gained for a scientific knowledge of nature. Such a
conception of an immaterial force, which at the first creates
matter, is an article of faith which has nothing whatever
to do with human science. Where faith commences, science
ends. Both these workings of the human mind must he
strictly kept apart from each other. Faith has its origin in
the poetic imagination ; knowledge, on the other hand,
originates in the reasoning intelligence of man. Science
has to pluck the blessed fruits from the tree of knowledge,
unconcerned whether these conquests trench upon the
poetical imaginings of faith or not.

If, therefore, science makes the " non-miraculous history
of creation " its highest, most difficult, and most compre-
hensive problem, it must accept as its idea of creation the
second explanation of the word, viz. the coming into being
of the form of natural bodies. In this way geology, which
investigates the origin of the inorganic surface of the earth
as it now appears, and the manifold historical changes in
the form of the solid crust of the earth, may be called the
history of the creation of the earth. In like manner, the
history of the development of animals and plants, which
investigates the origin of living forms, and the manifold
historical changes in animal and vegetable forms, may be
termed the history of the creation of organisms. As, how-
ever, in the idea of creation, although used in this sense,
the unscientific idea of a creator existing outside of matter,

IO THE HISTOKY OF OEBATION.

and changing it, may easily creep in, it will perhaps be
better in future to substitute for it the more accurate term,
development.

The great value which the History of Development pos-
sesses for the scientific understanding of animal and Vege-
table forms, has now for half a century been so generally
acknowledged that, without it, it would be impossible to
make any sure progress in organic morphology, or the
theory of forms. But the history of development has
generally been understood to embrace only one part of this
science, namely, that of. organic individuals, usually called
Embryology, but more correctly and comprehensively,
Ontogeny. But, besides this, there is another history
of development of organic species, genera, and tribes
. (phyla), which has the most important relations to the
former.

The subject of this is furnished to us by the science of
petrifactions, or palaeontology, which shows us that each
tribe of animals and plants, during different periods of the
earth's history, has been represented by a series of entirely
different genera and species. Thus, for example, the tribe
of vertebrated animals was represented by classes of fish,
amphibious animals, reptiles, birds, and mammals, and each
of these groups, at different periods, by quite different kinds.
This palaeontological history of the development of organ-
isms, which we may term Phylogeny, stands in the most
important and remarkable relation to the other branch of
organic history of development, I mean that of individuals,
or Ontogeny. On the whole, the one runs parallel to the
other. In fact, the history of individual development, or
Ontogeny, is a short and quick recapitulation of the slow

BIOLOGY REFORMED. II

and gradual palseontological development, or Phylogeny,
dependent on the laws of Inheritance and Adaptation.

As I shall have, later, to explain this most interesting
and important law of nature more fully, I .shall not dwell
further upon it here, and merely call attention to the fact
that it can only be explained and its causes understood by
the Theory of Descent, while without that theory it remains
completely incomprehensible and inexplicable. The Theory
of Descent in the same way shows us why individual
animals and plants must develop at all, and why they do
not come into life at once in a perfect and developed state.
No supernatural history of creation can in any way explain
to us the great mystery of organic development. To this
most weighty question, as well as to all other biological
questions, the Theory of Descent gives us perfectly satis-
factory answers — and always answers which refer to purely
mechanical causes, and point to purely physico-chemical/
forces as the causes of phenomena which we were formerly
accustomed to ascribe to the direct action of supernatural,
creative forces. Hence, by our theory the mystic veil of
the miraculous and supernatural, which has hitherto been
allowed to hide the complicated phenomena of this branch
of natural knowledge, is removed. All the departments of
Botany and Zoology, and especially the most important
portion of the latter, Anthropology, became reasonable.
The dimming mirage of mythological fiction can no longer
exist in the clear sunlight of scientific knowledge.

Of special interest among general biological phenomena
are those which are quite irreconcilable with the usual
supposition, that every organism is the product of a creative
power, acting for a definite object. Nothing in this respect

12 THE HISTORY OF CEEATION.

caused the earlier naturalists greater difficulty than the
explanation of the so-called " rudimentary organs" — those
parts in animal and vegetable bodies which really have no
function, which have no physiological importance, and yet
exist in form. These parts deserve the most careful atten-
tion, although most persons know little or nothing about
them. Almost every organism, almost every animal and
plant possesses, besides the obviously useful arrangements
of its organization, other arrangements the purpose of which
it is utterly impossible to make out.

Examples of this are found everywhere. In the embryos
of many ruminating animals — among others, in our common
cattle — fore-teeth, or incisors, are found in the mid-bone of
the upper jaw, which never fully develop, and therefore
serve no purpose. The embryos of many whales — which
afterwards possess the well-known whalebone instead of
teeth — while still unborn, and while they take no nourish-
ment, have teeth in their jaws, which set of teeth never
comes into use. Moreover, most of the higher animals
possess muscles which are never employed ; even man has
such rudimentary muscles. Most of us are incapable of
moving our ears as we wish, although the muscles for this
movement exist, and although individual persons who have
taken the trouble to exercise these muscles do succeed in
moving their ears. It is still possible, by special exercise,
by the persevering influence of the will upon the nervous
system, to reanimate the almost extinct activity in the
existing but imperfect organs, which are on the road to
complete disappearance. Qn the other hand, we can no
longer do this with another set of small rudimentary
muscles, which still exist in the cartilage of the outer ear,

RUDIMENTARY ORGANS. 13

but which are always perfectly inactive. Our long-eared
ancestors of the Tertiary period — apes, semi-apes, and
pouched animals — like most other mammals, moved their
large ear-flaps freely and actively ; their muscles were much
more strongly developed and of great importance. In a
similar way, many varieties of dogs and rabbits, under the
influence of civilized life, have left off " pricking up " their
ears, and thereby have acquired imperfect auricular muscles
and loose-hanging ears, although their wild ancestors moved
their stiff ears in many ways.

Man has these rudimentary organs also on other parts of
his body ; they are of no importance to life, and never per-
form any function. One of the most remarkable, although
the smallest organ of this kind, is the little crescent-like
fold, the so-called " plica semilunaris," which we have in the
inner corner of the eye, near the root of the nose. This in-
significant fold of skin, which is quite useless to our eye,
is the imperfect remnant of a third inner eyelid which,
besides the upper and under eyelid, is highly developed in
other mammals, and in birds and reptiles. Even our very
remote ancestors of the Silurian period, the Primitive Fishes,
seem to have possessed this third eyelid, the so-called nicti-
tating membrane. For many of their nearest kin, who still
exist in our day but little changed in form, viz. many
sharks, possess a very strong nictitating membrane, which
they can draw right across the whole eyeball, from the
inner corner of the eye.

> Eyes which do not see form the most striking example of
rudimentary organs. These are found in very many animals,
which live in the dark, as in caves or underground. Their
eyes often exist in a well-developed condition, but they are

14 THE HISTORY OP CREATION.

covered by membrane, so that no ray of light can enter,
and they can never see. Such eyes, without the function
of sight, are found in several species of moles and mice which
live underground, in serpents and lizards, in amphibious
animals (Proteus, Cascilia), and in fishes"; also in numerous
invertebrate animals, which pass their lives in the dark, as
do many beetles, crabs, snails, worms, etc.

An abundance of the most interesting examples of rudi-
mentary organs is furnished by Comparative Osteology, or
the study of the skeletons of vertebrate animals, one of the
most attractive branches of Comparative Anatomy. In
most of the vertebrate animals we find two pairs of iimbs
on the body, a pair of fore-legs and a pair of hind-legs.
Very often, however, one or the other pair is imperfect ; it
is seldom that both are, as in the case of serpents and some
varieties of eel-like fish. But some serpents, viz. the giant
serpents (Boa, Python), have still in the hinder portion of
the body some useless little bones, which are the remains of
lost hind-legs.

In like manner the mammals of the whale tribe (Cetacea),
which have only fore-legs fully developed (breast-fins), have
further back in their body another pair of utteriy superfluous
bones, which are remnants of undeveloped hind-legs. The
same thing occurs in many genuine fishes, in which the
hind-legs have in like manner been lost.

Again, our slow-worm (Anguis), and some other lizards,
possess no fore-legs, although they have a perfect shoulder
apparatus within their bodies, which should serve as a
means of affixing the legs. Moreover, in various vertebrate
animals, the single bones of both pairs of legs are found
in all the different stages of imperfection, and often the

RUDIMENTARY ORGANS. 15

degenerate bones and those muscles belonging to them are
partially preserved, without their being able in any way to
perform any function. The instrument is still there, but it
can no longer play.

Moreover, we can, almost as generally, find rudimentary
organs in the blossoms of plants, inasmuch as one part or
another of the male organs of propagation — the stamen and
anther, or of the female organs of propagation — the style,
germ, etc. — is more or less imperfect or abortive. Among
these we can trace, in various closely connected species of
plants, the organ in all stages of degeneration. Thus, for
example, the great natural family of lip-blossomed plants
(Labiatae), to which the balm, peppermint, marjoram, ground-
ivy, thyme, etc., belong, are distinguished by the fact that
their mouth-like, two-lipped flower contains two long and
two short stamens. But in many individual plants of this
family, e.g. in different species of sage, and in the rosemary,
only one pair of stamens is developed ; the other pair is more
or less imperfect, or has quite disappeared. Sometimes
stamens exist, but without the anthers, so that they are
utterly useless. Less frequently the rudiment or imperfect
remnant'Of a fifth stamen is found, physiologically (for the
functions of life) quite useless, but morphologically (for the
knowledge of the form and of the natural relationship) a
most valuable organ. In my " General Morphology of
Organisms," 4 in the chapter on " Purposelessness, or Dystele-
ology," I have given a great number of other examples
("Gen. Morph.,"ii. 226).

No biological phenomenon has perhaps ever placed
zoologists or botanists in greater embarrassment than these
rudimentary or abortive organs. They are instruments

1 6 THE HISTORY OF CREATION.

without employment, parts of the body which exist without
performing any service — adapted for a purpose, but without
in reality fulfilling that purpose. When we consider the
attempts which the earlier naturalists have made in order
to explain this mystery, we can scarcely help smiling at the
strange ideas to which they were led. Being unable to find
a true explanation, they came, for example, to the conclu-
sion that the Creator had placed these organs there " for the
sake of symmetry," or they believed that it had appeared
unwise and unsuitable to the Creator (seeing that their
nearest kin did possess such organs) that these organs
should be completely wanting in creatures, where they
are incapable of performing a function, and where it cannot
be otherwise from the special mode of life. In compensation
for the non-existing function, he had at least furnished
them with the outward but empty form; much in the same
manner as civil officers, in uniform, are furnished with an
innocent sword, which is never drawn from the scabbard.
I scarcely believe, however, that any of my readers will be
content with such an explanation.

Now, it is precisely this widely spread and mysterious
phenomenon of rudimentary organs, in regard to which all
other attempts at explanation fail, which is perfectly ex-
plained, and indeed in the simplest and clearest way, by
Darwin's Theory of Inheritance and Adaptation. We can
trace the important laws of inheritance and adaptation in
the domestic animals which we breed, and the plants which
we cultivate ; and a series of such laws of inheritance have
already been established. Without going further into this
at present, I will only remark that some of them perfectly
explain, in a mechanical way, the existence of rudimentary

EUDIMENTAEY ORGANS. 1 7

organs, so that we must look upon the appearance of such
structures as an entirely natural process, arising from the
disuse of the organs.

By adaptation to special conditions of life, the formerly
active and really working organs have gradually ceased
to be used or employed. In consequence of their not being
exercised they have become more and more imperfect, but
in spite of this have always been handed down from one
generation to another by inheritance, until at last they
vanish partially or entirely. Now, if we admit that all the
vertebrate animals mentioned above are derived from one
common ancestor, possessing two seeing eyes and two well-
developed pairs of legs, the different stages of suppression
and degeneration of these organs are easily accounted for in
such of the descendants as could no longer use them. In
like manner the various stages of suppression of the stamens,
originally existing to the number of five (in the flower-bud),
among the Labiatse is explained, if we admit that all the
plants of this family sprang from one common ancestor,
provided with five stamens.

I have here spoken somewhat fully of the phenomena of
rudimentary organs, because they are of the utmost general
importance, and because they lead us to the great, general,
and fundamental questions in philosophy and natural
science, for the solution of which the Theory of Descent
has now become the indispensable guide. As soon, in fact,
as, according to this theory, we acknowledge the exclusive
activity of physico-chemical causes in living (organic)
bodies, as well as in so-called inanimate (inorganic) nature,
we concede exclusive dominion to that view of the universe,
which we may designate as the mechanical, and which is

VOL. I. C

1 8 THE HISTOEY OF CREATION.

opposed to the teleological conception. If we compare all
the ideas of the universe prevalent among different nations
at different times, we can divide them all into two sharply
contrasted groups — a causal or mechanical, and a teleological
or vitalistic. The latter has prevailed generally in Biology
until now, and accordingly the animal and vegetable king-
doms have been considered as the products of a creative
power, acting for a definite purpose. In the contemplation
of every organism the unavoidable conviction seemed to
press itself upon us, that such a wonderful machine, so
complicated an apparatus for motion as exists in the
organism, could only be produced by a power analogous
to, but infinitely more perfect than, the power of man in
the construction of his machines.

However sublime the former idea of a Creator, and his
creative power, may have been ; however much it may be
divested of all human analogy, yet in the end this analogy
still remains unavoidable and necessary in the teleological
conception of nature. In reality the Creator must himself
be conceived of as an organism, that is, as a being who,
analogous to man, even though in an infinitely more perfect
form, reflects on his constructive power, lays down a plan
of his mechanisms, and then, by the application of suitable
materials, makes them answer their purpose. Such con-
ceptions necessarily suffer from the fundamental error of
anthropomorphism, or man-likening. In such a view,
however exalted the Creator may be imagined, we assign
to him the human attributes of designing a plan, and there-
from suitably constructing the organism. This is, in fact,
quite clearly expressed in that view which is most sharply
opposed to Darwin's theory, and which has found among

THE TELEOLOGICAL VIEW. 19

naturalists its most distinguished representative in Agassiz.
His celebrated work, " An Essay on Classification," which
is entirely opposed to Darwin's, and appeared almost at
the same time, has elaborated quite consistently, and to the
utmost extent, these anthropomorphic conceptions of the
Creator.

I maintain with regard to the much-talked-of " purpose
in nature," that it really has no existence but for those
persons who observe phenomena in animals and plants in
the most superficial manner. Without going more deeply
into the matter, we can see at once that the rudimentary
organs are a formidable obstacle to this theory. And, indeed,
every one who makes a really close study of the organization
and mode of life of the various animals and plants, and
becomes familiar with the reciprocity or inter-action of the
phenomena of life, and the so-called " economy of nature,"
must necessarily come to the conclusion that this
" purposiveness " no more exists than the much-talked-of
" beneficence " of the Creator. These optimistic views have,
unfortunately, as little real foundation as the favourite
phrase, the " moral order of the universe," which is illustrated
in an ironical way by the history of all nations. The
dominion of the "moral" popes, and their pious inquisition,
in the mediaeval times, is not less significant of this than
the prevailing militarism, with its "moral" apparatus of
needle-guns and other refined instruments of murder, or
the pauperism which is the inseparable accompaniment of
our refined civilization.

— If we closely examine the common life and the mutual
relations between plants and animals (man included), we
shall find everywhere, and at all times, the very opposite of

20 THE HISTORY OF CREATION.

that kindly and peaceful social life which the goodness of
the Creator ought to have prepared for his creatures — we
shall rather find everywhere a pitiless, most embittered
Struggle of All against All. Nowhere in nature, no matter
where we turn our eyes, does that idyllic peace exist, of
which poets sing; we find everywhere a struggle and a
striving to annihilate neighbours and competitors. Passion
and selfishness — conscious or unconscious — is everywhere
the motive force of life. The well-known words of Schiller —

" The world is perfect, save where man
Comes in with his strife,"*

are beautiful, but, unfortunately, not true. Man in this
respect certainly forms no exception to the rest of the
animal world. The remarks which we shall have to make
on the theory of " Struggle for Existence " will sufficiently
justify this assertion. It is, in fact, Darwin who has placed
this important point, in its high and general significance,
very clearly before our eyes, and the chapter in his theory
which he himself calls " Struggle for Existence " is one of
the most important parts of it.

Whilst, then, we emphatically oppose the vital or
teleological view of animate nature which presents animal
and vegetable forms as the productions of a kind Creator,
acting for a definite purpose, or of a creative, natural force
acting for a definite purpose, we must, on the other hand,
decidedly adopt that view of the universe which is called the
mechanical or causal. It may also be called the monistic,
or single-principle theory, as opposed to the twofold prin-
ciple, or dualistic theory, which is necessarily implied in

* " Die Welt ist vollkommen iiberaH

Wo der Mensch nioht hinkommt mit seiner Qual."

PHYSICS AND BIOLOGY. 21

the teleological conception of the universe. The mechanical
view of nature has for many years been so firmly established
in certain domains of natural science, that it is here un-
necessary to say much about it. It no longer occurs to
physicists, chemists, mineralogists, or astronomers, to seek
to find in the phenomena which continually appear before
them in their scientific domain the action of a Creator
acting for a definite purpose. They universally, and with-
out hesitation, look upon the phenomena which appear in
their different departments of study as the necessary and
invariable effects of physical and chemical forces which are
inherent in matter. Thus far their view is purely material-
istic, in a certain sense of that " word of many meanings."

When a physicist traces the phenomena of motion in
electricity or magnetism, the fall of a heavy body, or the
undulations in the waves of light, he never, in the whole
course of his research, thinks of looking for the interference
of a supernatural creative power. In this respect, Biology,
as the science of so-called " animated " natural bodies, was
formerly placed in sharp opposition to the above-mentioned
inorganic natural sciences (Anorganology). It is true modern
Physiology, the science of the phenomena of motion in
animals and plants, has completely adopted the mechanical
view ; but Morphology, the science of the forms of animals
and plants, has not been affected at all by it. Morphologists,
in spite of the position of physiology, have continued, as
before, in opposition to the mechanical view of functions, to
look upon the forms of animals and plants as something
which cannot be at all explained mechanically, but which
must owe its origin necessarily to a higher, supernatural
creative power, acting for a definite purpose.

22 THE HISTOEY OF CREATION.

In this general view it is quite indifferent whether the
creative power be worshipped as a personal god, or whether
it be termed the power of life (vis vitalis), or final cause
(causa finalis). In every case, to express it in one word, its
supporters have recourse to a miracle for an explanation.
They throw themselves into the arms of a poetic faith,
which as such can have no value in the domain of scientific
knowledge.

All that was done before Darwin, to establish a natural
mechanical conception of the origin of animals and plants,
has been in vain, and until his time no theory gained a
general recognition. Darwin's theory first succeeded in
doing this, and thus has rendered an immense service. For
the idea of the unity of organic and inorganic nature
is now firmly established ; and that branch of natural
science which had longest and most obstinately opposed
mechanical conception and explanation, viz. the science of
the structure of animate forms, their significance and origin,
is launched on to precisely the same road towards perfection
as that along which all the rest of the natural sciences are
travelling. The unity of all natural phenomena is by
Darwin's theory finally established.

This unity of all nature, the animating of all matter, the
inseparability of mental power and corporeal substance,
Goethe has asserted in the words, " Matter can never exist
and be active without mind, nor can mind without matter."
These first principles of the mechanical conception of the
universe have been taught by the great monistic philosophers
of all ages. Even Democritus of Abdera, the immortal
founder of the Atomic theory, clearly expressed them about
500 years before Christ ; but grand Spinoza, and the great

ALL NATURE IS ANIMATE. 23

Dominican friar, Giordano Bruno, did so even more ex-
plicitly. The latter was burnt at the stake for this, by the
Christian inquisition in Rome, on the 17th of Feb., 1600, on
the same day on which, 36 years before, Galileo, his great
fellow-countryman and fellow-worker, was born. On the
Campo di Fiori in Rome, where that funeral pile once stood,
free Italy a short time ago (in July, 1889) unveiled a
monument erected to the memory of the great martyr of
the monistic theory; an eloquent sign of the immense
change which time has wrought.

By the Theory of Descent we are for the first time enabled
to conceive of the unity of nature in such a manner that
a mechanico-causal explanation of even the most intricate
organic phenomena, for example, the origin and structure
of the organs of sense, is no more difficult (in a general
way) than is the mechanical explanation of any physical
process; as, for example, earthquakes, the courses of the
wind, or the currents of the ocean. We thus arrive at the
extremely important conviction that all natural bodies
which are known to us are equally animated, that the
distinction which has been made between animate and
inanimate bodies does not exist. When a stone is thrown
into the air, and falls to earth according to definite laws, or
when in a solution of salt a crystal is formed, or when
sulphur and quicksilver unite in forming cinnabar, the
phenomenon is neither more nor less a mechanical manifesta-
tion of life than the growth and flowering of plants, than
the propagation of animals or the activity of their senses,
than the perception or the formation of thought in man.
The forces of nature present themselves here merely in
different combinations and forms, sometimes simpler, some-

24 THE HISTORY OF CREATION.

times more complex. Bound elasticities become free and
pass over into living forces, or vice versd. This restoration
of the monistic conception of nature constitutes the chief
and most comprehensive merit of our new theory of
development, and is the crown of modern natural science.

( 2 5 )

CHAPTER II.

SCIENTIFIC JUSTIFICATION OF THE THEORY OF DE-
SCENT. HISTORY OF CREATION ACCORDING TO
LINN.EUS.

The Theory of Descent, or Doctrine of Filiation, as the Monistic Explana-
tion of Organic Natural Phenomena. — Its Comparison with Newton's
Theory of Gravitation. — Limits of Scientific Explanation and of Human
Knowledge in general. — All Knowledge founded originally on Sensuous
Experience, & posteriori. — Transition of a posteriori Knowledge, by In-
heritance, into ^priori Knowledge.- — Contrast between the Supernatural
Hypotheses of the Creation according to Linnaaus, Cnvier, Agassiz, and
the Natural Theories of Development according to Lamarck, Goethe,
and Darwin. — Connection of the former with the Monistic (mechanical),
of the latter with the Dualistic Conception of the Universe. — Monism
and Materialism. — Scientific and Moral Materialism. — The History of
Creation according to Moses. — Linnaeus as the Founder of the Systematic
Description of Nature and Distinction of Species. — Linnaeus' Classifica-
tion and Binary Nomenclature. — Meaning of Linnaeus' Idea of Species.
— His History of Creation. — Linnaeus' View of the Origin of Species.

The value which every scientific theory possesses is
measured by the number and importance of the objects
which can be explained by it, as well as by the simplicity
and universality of the causes which are employed in it as
grounds of explanation. On the one hand, the greater the
number and the more important the meaning of the
phenomena explained by the theory, and the simpler, on
the other hand, and the more general the causes which the
theory assigns as explanations, the greater is its scientific

26 THE HISTORY OF CREATION.

value, the more safely we are guided by it, and the more
strongly are we bound to adopt it.

Let us call to mind, for example, that theory which has
ranked up to the present time as the greatest achievement
of the human mind — the Theory of Gravitation, which
Newton, two hundred years ago, established in his Mathe-
matical Principles of Natural Philosophy. Here we find
that the object to be explained is as large as one can well
imagine. He undertook to reduce the phenomena of the
motion of the planets, and the structure of the universe, to
mathematical laws. As the most simple cause of these in-
tricate phenomena of motion, Newton established the law
of weight or attraction, the same law which is the cause of
the fall of bodies, of adhesion, cohesion, and many other
phenomena.

If we apply the same standard of valuation to Darwin's
theory, we must arrive at the conclusion that this theory,
also, is one of the greatest achievements of the human mind,
and that it may be placed quite on a level with Newton's
Theory of Gravitation. Perhaps this opinion will seem a
little exaggerated, or at any rate very bold, but I hope in
the course of this treatise to convince the reader that this
estimate is not too high. In the preceding chapter, some
of the most important and most general phenomena in
organic nature, which have been explained by Darwin's
theory, have been named. Among them are the variations
in form which accompany the individual development of
organisms, most varied and complicated phenomena, which
until now presented the greatest difficulties in the way of
mechanical explanation, that is, in the tracing of them to
active causes. We have mentioned the rudimentary organs.

DIVISION OF LABOUR. 27

those exceedingly remarkable structures in animals and
plants which have no object and refute every teleological
explanation seeking for the final purpose of the organism.
A great number of other phenomena might have been men-
tioned, which are no less important, and are explained in
the simplest manner by Darwin's reformed Theory of
Descent. For the present I will only mention the phenomena
presented to us by the geographical distribution of animals
and plants on the surface of our planet, as well as the
geological distribution of the extinct and petrified organisms
in the different strata of the earth's crust. These important
palseontological and geographical phenomena, which were
formerly only known to us as facts, are now traced to their
active causes by the Theory of Descent.

The same statement applies further to all the general
laws of Comparative Anatomy, especially to the great law
of division of labour or separation (polymorphism, or dif-
ferentiation), a law which determines the form or structure
of human society, as well as the organization of individual
animals and plants. It is this law which necessitates an
ever increasing variety, as well as a progressive develop-
ment of organic forms. This law of the division of labour
has, up to the present time, been only recognized as a fact,
and it, like the law of progressive development, or the law
of progress which we perceive active everywhere in the
history of nations (as also in that of animals and plants), is
explained by Darwin's Doctrine of Descent. Then, if we
turn our attention to the great whole of organic nature, if
we compare all the individual groups of phenomena of this
immense domain of ljfe, it cannot fail to appear, in the light
of the Doctrine of Descent, no longer as the ingeniously

28 THE HISTOEY OF CREATION.

designed work of a Creator building up according to a
definite purpose, but as the necessary consequence of active
causes, which are inherent in the chemical combination of
matter itself, and in its physical properties.

In fact, we can most positively assert, and I hope to
justify this assertion in the course of these pages, that by
the Doctrine of Filiation, or Descent, we are enabled for
the first time to reduce all organic phenomena to a single
law, and to discover a single active cause for the infinitely
intricate mechanism of the whole of this rich world of
phenomena. In this respect, Darwin's theory stands quite
on a level with Newton's Theory of Gravitation ; indeed, it
even rises higher than Newton's theory !

The grounds of explanation, moreover, are equally simple
in the two theories. In explaining this most intricate
world of phenomena, Darwin does not make use of new or
hitherto unknown properties of matter, nor does he, as
one might suppose, make use of discoveries of new com-
binations of matter or of new forces of organization ; but
it is simply by extremely ingenious combination, by the
synthetic comprehension, and by the thoughtful comparison
of a number of well-known facts, that Darwin has solved
the "holy mystery" of the living world of forms. The
consideration of the interchanging relations which exist
between two general properties of organisms, viz. Inherit-
ance and Adaptation, is what has here been of the first
importance. Merely by considering the relations between
these two vital actions or physiological functions of organ-
isms, also further by considering the reciprocal inter-action
which all animals and plants, living in one and the same
place, necessarily exert on one another — solely by the

LAMAKCK AND DARWIN. 29

correct estimate of these simple facts, and by skilfully
combining them, Darwin has succeeded in finding the true
active causes (causae efficientes) of the immensely intricate
world of forms in organic nature.

In any case we are in duty bound to accept this theory
till a better one be foixnd, which will undertake to explain
the same amount of facts in an equally simple manner.
Until now we have been in utter want of such a theory.
The fundamental idea that all different animal and vege-
table forms must be descended from a few or even from one
single, most simple primary form, was indeed not new. This
idea was long since distinctly formulated — first by the great
Lamarck, at the beginning of our century. But Lamarck
in reality only expressed the hypothesis of the Doctrine of
Filiation, without establishing it by an explanation of the
active causes. And it is just the demonstration of these
causes which marks the extraordinary progress which
Darwin's theory has made beyond that of Lamarck. In
the physiological properties of Inheritance and Adaptation
of organic matter, Darwin discovered the true cause of the
genealogical relationship o£ organisms. It was not possible
for the genius of Lamarck in his day to command that
colossal material of biological facts which has been collected
by the patient zoological and botanical investigations of the
last eighty years, and which has been used by Darwin as an
overpowering apparatus of evidence.

Darwin's theory is therefore not what his opponents fre-
quently represent it as being — an unwarranted hypothesis
taken up at random. It is not for zoologists or botanis£s to
accept or reject this as an explanatory theory, as they
please ; they are rather compelled and obliged to accept it,

30 THE HISTORY OF CREATION.

according to the general principle observed in all natural
sciences, that we must accept and retain for the explanation
of phenomena any theory which, though it has only a
feeble basis, is compatible with the actual facts — until it is
replaced by a better one. If we do not adopt it, we re-
nounce a scientific explanation of phenomena, and this is,
in fact, the position which many biologists still maintain.
They look upon the whole domain of animate nature as a
perfect mystery, and upon the origin of animals and plants,
the phenomena of their development and affinities, as quite
inexplicable and miraculous; in fact, they will not allow
that there can be a true understanding of them.

Those opponents of Darwin who do not exactly wish to
renounce a scientific explanation are in the habit of saying,
"Darwin's theory of the common origin of the different
species is only one hypothesis; we oppose to it another,
the hypothesis that the individual animal and vegetable
species have not developed one from another by descent,
but that they have come into existence independently of
one another, by a still undiscovered law of nature." But as
long as it is not shown how this coming into existence is
to be conceived of, and what that " law of nature " is — as
long as not even probable grounds of explanation can be
brought forward to account for the independent coming
into existence of animal and vegetable species, so long this
counter-hypothesis is in fact no hypothesis, but an empty
unmeaning phrase. Darwin's theory ought, moreover, not
to be called an hypothesis. For a scientific hypothesis
is a supposition, postulating the existence of unknown
properties or motional phenomena of natural bodies, which
properties have not as yet been observed by the experience

THE MEANING OF EXPLANATION. 3 1

of the senses. But Darwin's theory does not assume such
unknown conditions; it is based upon general properties
of organisms that have long been recognized, and — as has
been remarked — it is the exceedingly ingenious and com-
prehensive combination of a number of phenomena which
had hitherto stood isolated, which gives the theory its
extraordinarily great and intrinsic value. By it we are
for the first time in a position to demonstrate an active
cause for all the known morphological phenomena in the
animal and vegetable kingdoms ; and, in fact, this cause is
always one and the same, viz. the alternate action of Adap-
tation and Inheritance, therefore a physiological, that is, a
physico-chemical or mechanical, relationship. For these
reasons the acceptance of the Doctrine of Filiation, as
mechanically established by Darwin, is a binding and un-
avoidable necessity for the whole domain of zoology and
botany.

As, therefore, in my opinion the immense importance of
our new theory of development lies in the fact that it has
mechanically explained those organic phenomena of forms
which had hitherto been unexplained, it is perhaps necessary
that I should here say a few words about the different
ideas connected with the word " explanation." It is very
frequently said, in opposition to the Transmutation theory,
that it does indeed fully explain those phenomena by In-
heritance and Adaptation, but that it does not at the same
time explain these properties of organic matter, and that
therefore we do not arrive at first causes. This objection
is quite correct, but it applies equally to all explanations
of phenomena. We nowhere arrive at a knowledge of first
causes. The origin of every simple salt crystal, which we

32 THE HISTOEY OP CREATION.

obtain by evaporating its mother liquor, is no less mysterious
to us, as far as concerns its first cause, and in itself no less
incomprehensible than the origin of every animal which is
developed out of a simple cell. In explaining the most
simple physical or chemical phenomena, as the falling of a
stone, or the formation of a chemical combination, we
arrive, by discovering and establishing the active causes —
for example, the gravitation or the chemical affinity — at
other remoter phenomena, which in themselves are mys-
terious. This arises from the limitation or relativity of our
powers of understanding. We must not forget that human
knowledge is absolutely limited, and possesses only a
relative extension. It is, in its essence, limited by the
very nature of our senses and of our brains.

All knowledge springs primarily from sensuous percep-
tions. In opposition to this statement, the innate, & priori
knowledge of man may be brought up ; but we can see that
the so-called d priori knowledge can by Darwin's theory
be proved to have been acquired a posteriori, being based
on experience as its first cause. Knowledge which is based
originally upon purely empirical observations, and which is
therefore a purely sensuous experience, but has then been
transmitted from generation to generation by inheritance,
appears in later generations as if it were independent,
innate, and cb priori, in the same way as the so-called
instincts of animals. In our early animal ancestors, all our
so-called " & priori knowledge " was originally acquired d,
posteriori, and only gradually became a priori by inherit-
ance. It is based in the first instance upon experiences,
and the laws of Inheritance and Adaptation prove that
knowledge d priori and knowledge a posteriori cannot

FIEST CAUSES NOT KNOWN. 33

rightly be placed in opposition, as is usually done. On the
contrary, sensuous experience is the original source of all
knowledge. For this reason alone, all our knowledge is
limited, and we can never apprehend the first causes of any
phenomena. The force of crystallization, the force of gravi-
tation, and chemical affinity remain in themselves just as
incomprehensible as Adaptation and Inheritance or Will
and Consciousness.

Seeing that the doctrine of descent explains from a single
point of view the totality of all those phenomena of which
we have given a brief survey, that it demonstrates one and
the same quality of the organism as the active cause in all
cases, we must allow that it gives us for the present all
that we can desire. Moreover, we have good reason to
hope that at some future time we shall learn to explain the
first causes at which Darwin has arrived, namely, the
properties of Adaptation and Inheritance; and that we shall
succeed in discovering in the composition of albuminous
matter certain molecular relations as the remoter, simpler
causes of these phenomena. There is indeed no prospect of
this in the immediate future, and we content ourselves for
the present with the tracing back of organic phenomena to
two mysterious properties, just as in the case of Newton's
theory we are satisfied with tracing the planetary motions
to the force of gravitation, which itself is likewise a mystery
to us and not cognizable in itself.

Before commencing our principal task, which is the
careful discussion of the Doctrine of Descent, and the
consequences that arise out of it, let us take an historical
retrospect of the most important and most widely spread of
those views, which before Darwin men had elaborated con-

VOL. I. D

34 THE HISTORY OF CREATION.

cerning organic creation, and the coming into existence of
the many animal and vegetable species. In doing this I
have no intention of entertaining the reader with a state-
ment of all the innumerable stories about the creation
which have been current among the different human
species, races, or tribes. However interesting and gratify-
ing this task would be, from an ethnographical point of
view, as well as in a history of civilization, it would lead
us here much too far from our subject. Besides, the great
majority of all these legends about creation bear too clearly
the stamp of arbitrary fiction, and of a want of a close
observance of nature, to be of interest in a scientific treat-
ment of the history of creation. I shall therefore only
select the Mosaic history from among those that are not
founded on scientific investigation, on account of the un-
paralleled influence which it has gained in the western
civilized world ; and then I shall immediately take up the
scientific hypothesis about creation, which originated with
Linnseus as late as the commencement of last century.

All the different conceptions which man has ever formed
about the coming into existence of the different animal and
vegetable species may conveniently be divided into two
great contrasted groups — the natural and supernatural his-
tories of creation.

These two groups, on the whole, correspond with the two
different principal forms of the human notions of the uni-
verse which we have already contrasted as the monistic and
the diialistic conception of nature. In the usual dualistic or
teleological (vital) conception of the universe, organic nature
is regarded as the purposely executed production of a Creator
working according to a definite plan. Its adherents see in

MONISM VEBSUS DUALISM. 35

every individual species of animal and plant an " embodied
creative thought," the material expression of a definite first
cause (causa finalis) acting for a set purpose. They must
necessarily assume supernatural (not mechanical) processes
for the origin of organisms. "With justice, we may therefore
designate their scheme of the world's growth as the Super-
natural History of Creation. Among all such teleological
histories of creation, that of Moses has gained the greatest
influence, since even so distinguished a naturalist as Lin-
naeus has claimed admittance for it in Natural Science.
Cuvier's and Agassiz's view of creation also belong to this
group, as do in fact those of the great majority of the earlier
naturalists.

On the other hand, the theory of development carried out
by Darwin, which we shall have to treat of here as the Non-
oniraculous or Natural History of Creation, and which has
already been put forward by Goethe and Lamarck, must, if
carried out logically, lead to the monistic or mechanical
(causal) conception of the universe. In opposition to the
dualistic or teleological conception of nature, our theory
considers organic, as well as inorganic, bodies to be the neces-
sary products of natural forces. It does not see in every in-
dividual species of animal and plant the embodied thought
of a personal Creator, but the expression for the time being
of a mechanical process of development of matter, the ex-
pression of a necessarily active cause, that is, of a mechanical
cause (causa efficiens). Where teleological Dualism seeks
the arbitrary thoughts of a capricious Creator in the miracles
of creation, causal Monism finds in the process of develop-
ment the necessary effects of eternal immutable laws of
nature.

2,6 THE HISTORY OF CBEATION.

The Monism here maintained by us is often considered
identical with Materialism. Now, as Darwinism, and in
fact the whole theory of development, has been designated
as "materialistic," I cannot avoid here at once guarding
myself against this ambiguous word, and against the malice
with which, in certain quarters, it is employed to stigmatize
our doctrine.

By the word "Materialism," two completely different
things are very frequently confounded and mixed up, which
in reality have nothing whatever to do with each other,
namely, scientific and moral materialism. Scientific mate-
rialism, which is identical with our Monism, affirms in
reality no more than that everything in the world goes on
naturally — that every effect has its cause, and every cause
its effect. It merely assigns to causal law — that is, the law
of a necessary connection between cause and effect — its
place over the entire series of phenomena that can be
known. At the same time, scientific materialism absolutely
rejects every belief in the miraculous, and every conception,
in whatever form it appears, of supernatural processes.
Accordingly, nowhere in the whole domain of human know-
ledge does it recognize real metaphysics, but throughout
only physics ; it makes the inseparable connection between
matter, form, and force become self-evident. This scientific
materialism has long since been so universally acknowledged
in the wide domain of inorganic science, in Physics and
Chemistry, in Mineralogy and Geology, that no one any
longer doubts its sole authority. But in Biology, or Organic
science, the case is very different; here its value is still
continually a matter of dispute in many quarters. There
is, however, nothing else which can be set up against it,

MOEAL MATERIALISM. 37

excepting the metaphysical spectre of a vital power, or
empty theological dogma. If, however, we can prove that
all nature, so far as it can be known, is only one, that the
same " great, eternal, iron laws " are active in the life of
animals and plants, as in the growth of crystals and in the
force of steam, we may with reason maintain the monistic
or mechanical view of things throughout the domain of
Biology — in Zoology and Botany — whether it be stigmatized
as " materialism " or not. In such a sense all exact science,
and the law of cause and effect at its head, is purely
materialistic. But with equal justice it might be termed
purely " spiritualistic," if only, as a consequence, the monistic
conception were applied to all phenomena without excep-
tion. For it is precisely by means of this consistent unity
that our modern monism constitutes itself the mediator
between idealism and realism, and the adjuster of one-sided
spirtualism and materialism.

Moral, or ethical Materialism, is something quite distinct
from scientific materialism, and has nothing whatever in
common with the latter. This " actual " materialism pro-
poses no other aim to man in the course of his life than
the most refined possible gratification of his senses. It is
based on the delusion that purely material enjoyment
can alone give satisfaction to man ; but as he can find that
satisfaction in no one form of sensuous pleasure, he dashes
on weariedly from one to another. The profound truth that
the real value of life does not lie in material enjoyment,
but in moral action — that true happiness does not depend
upon external possessions, but only in a virtuous Course of
life — this is unknown to ethical materialism. We therefore
look in vain for such materialism among naturalists and

38 THE HISTORY OF CREATION.

philosophers, whose highest happiness is the intellectual
enjoyment of Nature, and whose highest aim is the know-
ledge of her laws. We find it in the palaces of ecclesi-
astical princes, and in those hypocrites who, under the
outward mask of a pious worship of God, solely aim at
hierarchical tyranny over, and material spoliation of, their
fellow-men. Blind to the infinite grandeur of the so-called
" raw material," and the glorious world of phenomena
arising from it — insensible to the inexhaustible charms
of Nature, and without a knowledge of her laws — they
stigmatize all natural science, and the culture arising from
it, as sinful " materialism," while really it is this which they
themselves exhibit in a most objectionable form. Satis-
factory proofs of this are furnished, not only by the whole
history of the " infallible " Popes, with their long series of
hideous crimes, but also by the history of the morals of
orthodoxy in every form of religion.

In order, then, to avoid in future the usual confusion of
this utterly objectionable Moral Materialism with our
Scientific Materialism, we think it necessary to call the
latter either Monism or Realism. The principle of this
Monism is the same as what Kant terms the " principle of
mechanism," and of which he expressly asserts, that without
it there can be no natural science at all. This principle is
quite inseparable from our Non-miraculous History of Crea-.
tion, and characterizes it as opposed to the teleological belief
in the miracles of a Supernatural History of Creation.

Let us now first of all glance at the most important of all
the supernatural histories of creation, I mean that of Moses,
as it has been handed down to us in the Bible, the ancient
document of the history and laws of the Jewish people.

THE MOSAIC COSMOGENY. 39

The Mosaic history of creation, since in the first chapter of
Genesis it forms the introduction to the Old Testament, has
enjoyed, down to the present day, general recognition in
the whole Jewish and Christian world of civilization. Its
extraordinary success is explained not only by its close
connection with Jewish and Christian doctrines, but also
by the simple and natural chain of ideas which runs
through it, and which contrasts favourably with the
confused mythology of creation current among most of the
other ancient nations. First the Lord God creates the earth
as an inorganic body ; then he separates light from dark-
ness, then water from the dry land. Now the earth has
become inhabitable for organisms, and plants are first
created, animals later — and among the latter the inhabitants
of the water and the air first, afterwards the inhabitants of
the dry land. Finally God creates man, the last of all
organisms, in his own image, and as the ruler of the earth.

Two great and fundamental ideas, common also to the
non-miraculous theory of development, meet us in this
Mosaic hypothesis of creation, with surprising clearness and
simplicity — the idea of separation or differentiation, and the
idea of progressive development or perfecting. Although
Moses looks upon the results of the great laws of organic
development (which we shall later point out as the necessary
conclusions of the Doctrine of Descent) as the direct actions
of a constructing Creator, yet in his theory there lies hidden
the ruling idea of a progressive development and a differen-
tiation of the originally simple matter. We can therefore
bestow our just and sincere admiration on the Jewish
lawgiver's grand insight into nature, and his simple and
natural hypothesis of creation, without discovering in it a

40 THE HISTORY OF CREATION.

so-called "divine revelation." That it cannot be such is
clear from the fact that two great fundamental errors are
asserted in it, namely, first, the geocentric error that the
earth is the fixed central point of the whole universe, round
which the sun, moon, and stars move; and secondly, the
anthropocentric error, that man is the premeditated aim of
the creation of the earth, for whose service alone all the
rest of nature is said to have been created. The former of
these errors was demolished by Copernicus' System of the
Universe in the beginning of the 16 th century, the latter
by Lamarck's Doctrine of Descent in the beginning of the
19th century.

Although the geocentric error of the Mosaic history was
demonstrated by Copernicus, and thereby its authority as
an absolutely perfect divine revelation was destroyed, yet
it has maintained, down to the present day, such influence,
that it forms in many wide circles the principal obstacle to
the adoption of a natural theory of development. Even in
our century, many naturalists, especially geologists, have
tried to bring the Mosaic theory into harmony with the
recent results of natural science, and have, for example,
interpreted Moses' seven days of creation as seven great
geological periods. However, all these ingenious attempts
at interpretation have so utterly failed, that they require
no refutation here. The Bible is no scientific book, but
consists of records of the history, the laws, and the religion
of the Jewish people, the high merit of which, as a history of
civilization, is not impaired by the fact that in all scientific
questions it has no commanding importance, and is full of
gross errors.

We may now make a great stride over more than three

LINN^US. 41

thousand years, from Moses, who died about the year 1480
before Christ, to Linnseus, who was born in the year 1707
after Christ. During this whole period no history of creation
was brought forward that gained any lasting importance,
or the closer examination of which would here be of any
interest. Indeed, during the last fifteen hundred years,
since Christianity gained its supremacy, the Mosaic history
of creation, together with the dogmas connected with it, has
become so generally predominant, that the 19th century is
the first that has dared positively to rise against it. Even
the great Swedish naturalist, Linnaeus, the founder of modern
natural history, linked his System of Nature most closely to
the Mosaic history of creation.

The extraordinary progress which Charles Linnaeus made
in the so-called descriptive natural sciences, consists, as is
well known, in his having established a system of nomencla-
ture of animals and plants, which he carried out in a manner
so perfectly logical and consistent, that down to the present
day it has remained in many respects the standard for all
succeeding naturalists engaged in the study of the forms of
animals and plants. Although Linnaeus' "Sy sterna, natures"
(published in 1735) was artificial, although in classifying
animal and vegetable species he only sought and employed
single parts as the foundation for his divisions, it has, never-
theless, gained the greatest success ; firstly, in consequence
of its being carried out consistently, and secondly, by its
nomenclature of natural bodies, which has become extremely
important, and at which we must here briefly glance.

Before Linnaeus' time, many vain attempts had been made
to throw light upon the endless chaos of different animal
and vegetable forms (then known) by adopting for them

42 THE HISTOEY OF CREATION.

suitable names and groupings ; but Linnaeus, by a happy
hit, succeeded in accomplishing this important and difficult
task, when he established the so-called "binary nomen-
clature." The binary nomenclature, or the twofold desig-
nation, as Linnaeus first established it, is still universally
applied by all zoologists and botanists, and will, no doubt,
maintain itself, for a long time to come, with undiminished
authority. It consists in this, that every species of animal
and plant is designated by two names, which stand to each
other in the same relation as do the christian and surnames
of a man. The special name which corresponds with the
christian name, and expresses the idea of " a species," serves
as the common designation of all individual animals or
plants, which are equal in all essential matters of form, and
are only distinguished by quite subordinate features. The
more general name, on the other hand, corresponding with
the surname, and which expresses the idea of a genus, serves
for the common designation of all the most nearly similar
kinds or species.

According to Linnaeus' plan, the more general and com-
prehensive generic name is written first ; the special subor-
dinate name of the species follows it. Thus, for example,
the common cat is called Felis domestica ; the wild cat,
Felis catus ; the panther, Felis pardus ; the jaguar, Felis
onca ; the tiger, Felis tigris ; the' lion, Felis leo. All these
six kinds of animals of prey are different species of one and
the same genus — Felis. Or, to add an example from the
vegetable kingdom, according to Linnseus' designation the
pine is Pinus abies ; the fir, Pinus picea ; the larch, Pinus
larix ; the Italian pine, Pinus pinea ; the Siberian stone
pine, Pinus cembra ; the knee timber, Pinus mughus ; the

THE LINN^AN NOMENCLATURE. 43

common pine, Pinus silvestris. All these seven kinds of
pines are different species of one and the same genus —
Pinus.

Perhaps this advance made by Linnaeus may seem to some
only of subordinate importance in the practical distinction
and designation of the variously formed organisms. - But
in reality it was of the very greatest importance, both from
a practical and theoretical point of view. For now, for the
first time, it became possible to arrange the immense mass
of different organic forms according to their greater or less
degree of resemblance, and to obtain an easy survey of the
general outlines of such a "system." Linnaeus facilitated
the tabulation and survey of this " system " of plants and
animals still more by placing together the most nearly
similar genera into so-called orders (ordines); and by
uniting the most nearly similar orders into still more com-
prehensive main divisions or classes. Thus, according to
Linnaeus, each of the two organic kingdoms were broken
up into a number of classes, the vegetable kingdom into
twenty-four, and the animal kingdom into six. Each class
again contains several orders. Every single order may
contain a number of genera, and, again, every single genus
several species.

Valuable as was Linnaeus' binary nomenclature in a prac-
tical way, in bringing about a comprehensive systematic
distinction, designation, arrangement, and division of the
organic world of forms, yet the incalculable theoretical
influence which it gained forthwith in relation to the
history of creation was no less important. Even now all
the important fundamental questions as to the history of
creation turn finally upon the decision of the very remote

44 THE HISTOEY OF CBEATION.

and unimportant question, What really are hinds or species 1
Even now the idea of organic species may be termed the
central point of the whole question of creation, the disputed
centre, about the different conceptions of which Darwinists
and Anti-Darwinists fight.

According to Darwin's opinion, and that of his adherents,
the different species of one and the same genus of animals
and plants are nothing else than differently developed
descendants of one and the same original primary form.
The different kinds of pine mentioned above would accord-
ingly have originated from a single primaeval form of pine.
In like manner the origin of all the species of cat mentioned
above would be traced to a single common form of Felis,
the ancestor of the whole genus. But further, in accordance
with the Doctrine of Descent, all the different genera of one
and the same order ought also to be descended from one
common primary ancestor, and so, in like manner, all orders
of a class from a single primary form.

On the other hand, according to the idea of Darwin's
opponents, all species of animals and plants are quite in-
dependent of each other, and only the individuals of each
species have originated from a single primary form. But if
we ask them how they conceive these original primary forms
of each species to have come into existence, they answer
with a leap into the incomprehensible, " They were created."

Linnaeus himself defined the idea of species in this
manner by saying, " There are as many different species as
there were different forms created in the beginning by the
infinite Being." (" Species tot sunt diversae, quot diversas
formas ab initio creavit infinitum ens.") In this respect,
therefore, he follows most closely the Mosaic history of

THE LINN^AN COSMOGENY. 45

creation, which in the same way maintains that animals
and plants were created " each one after its kind." Linnaeus,
accepting this, held that originally of each species of
animals and plants either a single individual or a pair had
been created ; in fact a pair, or, as Moses says, " a male and
a female" of those species •which have separate sexes, but of
those species in which each individual combines both sexual
organs (hermaphrodites), as for instance the earth-worm,
the garden and vineyard snails, as well as the great majority
of plants, a single individual.

Linnaeus further follows the Mosaic legend in regard to
the flood, by supposing that the great general flood destroyed
all existing organisms, except those few individuals of each
species (seven pairs of the birds and of clean animals, one
pair of unclean animals) which Noah saved in the ark, and
which were placed again on land, on Mount Ararat, after the
flood had subsided. He tried to explain the geographical
difliculty of the living together of the most different animals
and plants, as follows : Mount Ararat, in Armenia, being
situated in a warm climate, and rising over 16,000 feet in
height, combines in itself the conditions for a temporary
common abode of such animals as live in different zones.
Accordingly, animals accustomed to the polar regions could
climb up the cold mountain ridges, those accustomed to
a warm climate could go down to the foot of the mountain,
and the inhabitants of a temperate zone^could remain mid-
way up the mountain. From this point it was possible for
them to spread north and south over the earth.

It is scarcely necessary to remark that this Linnaean
hypothesis of creation, which evidently was intended to
harmonize most closely with the prevailing belief in the

46 THE HISTORY OF CREATION.

Bible, requires no serious refutation. When we consider
Linnaeus' clearness and sagacity in other matters, we may
doubt whether he believed it himself. As to the simulta-
neous origin of all individuals of each species from one pair
of ancestors respectively (or in the case of the hermaphro-
dite species, from one original hermaphrodite), it is clearly
quite untenable ; for, apart from other reasons, in the first
days after the creation, the few animals of prey would
have sufficed to have utterly demolished all the herbivorous
animals, as the herbivorous animals must have destroyed
the few individuals of the different species of plants. The
existence of such an equilibrium in the economy of nature
as obtains at present cannot possibly be conceived, if only
one individual of each species, or only one pair, had
originally and simultaneously been created.

Moreover, how little importance Linnaeus himself attached
to this untenable hypothesis of creation is clear, among
other things, from the fact that he recognized Hybridism
(crossing) as a source of the production of new species. He
assumed that a great number of independent new species
had originated by the interbreeding of two different species.
Indeed, such hybrids are not at all rare in nature, and it
is now proved that a great number of species, for example,
of the genus Rubus (bramble), mullen (Verbascum), willow
(Salix), thistle (Cirsium), are hybrids of different species of
these genera. We also know of hybrids .between hares and
rabbits (two species of the genus Lepus), further of hybrids
between different species of dog (genus Canis) and deer
(Cervus), etc., which can be propagated as independent
species. Nay, for many important reasons we are justified
in assuming that the rearing of bastards is a very pro-

HYBRIDISM. 47

ductive source for the origin of new species ; and this
source is quite independent of natural selection, by which
means, according to Darwin, most species have arisen. It
is probable that the very numerous forms of animals and
plants, which in our systematic classification we nowadays
enumerate as " good species," are nothing more than fruitful
bastards which have originated quite accidentally by the
successful commingling of the sexual products of the two
different species. This supposition is specially justified as
regards aquatic animals and plants. When we consider
what masses of different seed-cells and egg-cells constantly
come in contact in water, the widest scope seems thereby
given for the production of bastards.

It is certainly very remarkable that even Linnaeus asserted
the physiological (therefore mechanical) origin of new species
by this process of hybridism. It clearly stands in direct
opposition to the supernatural origin of the other species
by creation, which he accepted as put forward in the Mosaic
account. The one set of species would therefore have
originated by dualistic (teleological) creation, the other by
monistic (mechanical) development.

The great and well-merited authority which Linnaeus
gained by his systematic classification and by his other
services to Biology, was clearly the reason why his views
of creation also remained, throughout the whole of the last
century, undisputed and generally recognized. If through-
out systematic Zoology and Botany the distinctions,
classification, and designations of species, introduced by
Linnaeus, and the dogmatic ideas connected therewith had
not been maintained — more or less unaltered — we should
be at a loss to understand how his idea of an independent

48 THE HISTORY OF CREATION.

creation of single species could have held its ground up to
the present day. It is only owing to his great authority,
and through his attaching himself to the prevailing Biblical
belief, that his hypothesis of creation has retained its position
so long. '

( 49 )

CHAPTER III.

THE HISTORY OF CREATION ACCORDING TO CUVIER
AND AGASSIZ.

General Theoretical Meaning of the Idea of Species. — Distinction between
the Theoretical and Practical Definition of the Idea of Species. — Cuvier's
Definition of Species.— Merits of Cuvier as the IPonnder of Comparative
Anatomy. — Distinction of the Four Principal Forms (types or branches)
of the Animal Kingdom, by Cuvier and Bar. — Cuvier's Services to
Palaeontology. — His Hypothesis of the Revolutions of our Globe, and the
Epochs of Creation separated by them. — Unknown Supernatural Causes
of the Revolutions, and the subsequent New Creations. — Agassiz's
Teleological System of Nature. — His Conception of the Plan of Creation,
and its six Categories (groups in classification). — Agassiz's Views of the
Creation of Speoies. — Rude Conception of the Creator as a man-like
being in Agassiz's Hypothesis of Creation. — -Its internal Inconsistency
and Contradictions with the important Palseontological Laws discovered
by Agassiz.

The real matter of dissension in the contest carried on by
naturalists as to the origin of organisms, their creation and
development, lies in the conceptions which are entertained
about the nature of species. Naturalists either agree with
Linnseus, and look upon the different species as distinct
forms of creation, independent of one another, or they
assume with Darwin their blood-relationship. If we share
Linnfeus' view (which was discussed in our last chapter),
that the different organic species came into existence

VOL. I. E

50 THE HISTOKY OF CREATION.

independently — that they have no blood-relationship— we
are forced to admit a supernatural creation, and must
either suppose that every single organic individual was
a special act of creation (to which surely no naturalist will
agree), or we must derive all individuals of every species
from a single individual, or from a single pair, which did
not arise in a natural manner, but was called into being
by command of a Creator. In so doing, however, we turn
aside from the safe domain of a rational knowledge of
nature, and take refuge in the mythological belief in
miracles.

If, on the other hand, with Darwin, we refer the simi-
larity of form of the different species to real blood-relation-
ship, we must consider all the different species of animals
and plants as the altered descendants of one or a few most
simple original forms. Viewed in this way, the Natural
System of organisms (that is, their tree-like and branching
arrangement and division into classes, orders, families,
genera, and species) acquires the significance of a real genea-
logical tree, whose root is formed by those original archaic
forms which have long since disappeared. But a truly
natural and consistent view of organisms can assume no
supernatural act of creation for even those simplest original
forms, but only a coming into existence by spontaneous
generation* (archigony, or generatio spontanea). From
Darwin's view of the nature of species, we arrive therefore
at a natural theory of development; but from Linnaeus'
conception of the idea of species, we must assume a super-
natural dogma of creation.

Most naturalists after Linnaeus, whose great services in
* Archebiosis (Bastian), Abiogenesis (Huxley).

THE DOGMA OP SPECIES. 51

systematic and descriptive natural history won for him
such high authority, followed in his footsteps, and without
further inquiry into the origin of organization, they assumed,
in the sense of Linnseus, an independent creation of individual
species, in conformity with the Mosaic account of creation.
The foundation of their conception was based upon Lin-
naeus' words, " There are as many different species as there
were different forms created in the beginning by the Infinite
Being." We must here remark at once, without going
further into the definition of species, that all zoologists and
botanists in their classificatory systems, in the practical dis-
tinction and designation of species of animals and plants,
never troubled, or even could trouble, themselves in the
slightest degree about this assumed creation of the parent-
forms. In reference to this, one of our first zoologists, the
ingenious Fritz Muller, makes the following striking obser-
vation : " Just as in Christian countries there is a catechism
of morals, which every one knows by heart, but which no
one considers it his duty to follow, or expects to see followed
by others, — so zoology also has its dogmas, which are just
as generally professed as they are denied in practice,"
(" Fur Darwin," p. 71). 16

Linnseus' venerated dogma of species, up to quite recent
times, was just such an irrational dogma, and indeed for
that very reason most powerful. Although most naturalists
blindly submitted to it, yet they were, of course, never in a
position to demonstrate the descent of individuals belonging
to one species from the common, originally created, primitive
form. Zoologists and botanists, in their systems of nomen-
clature, confined themselves entirely to the similarity of
forms, in order to distinguish and name the different species.

52 THE HISTORY OF CREATION.

They placed in one species all organic individuals which
were very similar, or almost identical in form, and which
could only be distinguished from one another by very unim-
portant differences. On the other hand, they considered as
different species those individuals which presented more
essential or more striking differences in the formation of
their bodies. But of course this opened the flood-gates to
the most arbitrary proceedings in the systematic distinctions
of species. For as all the individuals of one species are
never completely alike in all their parts, but as every
species varies more or less, no one could point out which
degree of variation constituted a really " good species," or
which degree indicated a " mere variety."

This dogmatic conception of the idea of species, and the
arbitrary proceedings connected with it, necessarily led to
the most perplexing contradictions, and to the most unten-
able suppositions. This is clearly demonstrable in the case
of the celebrated George Cuvier (born in 1769), who next
to Linnaeus has exercised the greatest influence on the
study of zoology. In his conception and definition of the
idea of species, he agreed on the whole with Linnseus, and
shared also his belief in an independent creation of indi-
vidual species. Cuvier considered their immutability of
such importance that he was led to the foolish assertion,
"The immutability of species is a necessary condition of
the existence of scientific natural history." As Linnaeus'
definition of species did not satisfy him, he made an attempt
to give a more exact and, for systematic practice, a more
useful definition, in the following words : " All those indi-
vidual animals and plants belong to one species which can
be proved to be either descended from one another, or from

cuviee's definition op species. 53

common ancestors, or which are as similar to these as the
latter are among themselves."

In dealing with this matter, Cuvier reasoned in the
following manner : " In those organic individuals, of which
we know that they are descended from one and the same
common form of ancestors — in which, therefore, their com-
mon ancestry is empirically proved — there can be no doubt
that they belong to one species, whether they differ much
or little from one another, or whether they are almost alike
or very unlike. In like manner all those individuals also
belong to this species which differ no more from the latter
(those proved to be derived from a common stock) than
these differ from one another." In a closer examination of
this definition of species given by Cuvier, it becomes at
once evident that it is neither theoretically satisfactory nor
practically applicable. Cuvier, with this definition, began
to move in the same circle in which almost all subsequent
definitions of species have moved, through the assumption
of their immutability.

Considering the extraordinary authority which George
Cuvier has gained in the science of organic nature, and in
consequence of the almost unlimited supremacy which his
views exercised in zoology, during the first half of our
century, it seems appropriate here to examine his influence
a little more closely. This is all the more necessary as we
have to combat, in Cuvier, the most formidable opponent to
the Theory of Descent and the monistic conception of nature.

One of the many and great merits of Cuvier is that he
stands forth as the founder of Comparative Anatomy. While
Linnaeus established the distinction of species, genera, orders,
and classes mostly upon external characters, and upon sepa-

54 THE HISTORY OF CREATION.

rate and easily discoverable signs in the number, size, place,
and form of individual organic parts of the body, Cuvier
penetrated much more deeply into the essence of organiza-
tion. He demonstrated great and wide differences in the
inner structure of animals, as the real foundation of a
scientific knowledge and classification of them. He dis-
tinguished natural families in the classes of animals, and
established his natural system of the animal kingdom on
their comparative anatomy.

The progress from Linnaeus' artificial system to Ouvier's
natural system was exceedingly important. Linnaeus had
arranged all animals in a single series, which he divided
into six classes — two classes of Invei'tebrate, and four classes
of Vertebrate animals. He distinguished these artificially,
according to the nature of their blood and heart. Cuvier,
on the other hand, showed that in the animal kingdom there
were four great natural divisions to be distinguished, which
he termed Principal Forms, or General Plans, or Branches
of the animal kingdom (Euibranchements), namely: 1. The
Vertebrate animals (Vertebrata); 2. The Articulate animals
(Articulata) ; 3. The Molluscous animals (Mollusca) ; and 4*.
The Radiate animals (Radiata). He further demonstrated
that in each of these four branches a peculiar plan of struc-
ture or type was discernible, distinguishing each branch
from the three others. In the Vertebrate animals it is dis-
tinctly expressed by the form of the skeleton, or bony
framework, as also by the structure and position of the
dorsal nerve-chord, apart from many other peculiarities.
The Articulate animals are characterized by their ventral
nerve-chord and their dorsal heart. In Molluscs the sack-
shaped and non-articulate body is the distinguishing feature.

CUVIER AND BAR. 55

The Kadiate animals, finally, differ from the three other
principal forms by their body being the combination of four
or more main sections united in the form of radii (Paramera).

The distinction of these four principal forms of animals,
which has become extremely productive in the development
of zoology, is commonly ascribed entirely to Cuvier. How-
ever, the same thought was expressed almost simultaneously,
and independently of Cuvier, by Bar, one of our greatest
German naturalists, who did the most eminent service in
the study of animal development. Bar showed that in the
development of animals, also, four different main forms (or
types) must be distinguished. 20 These correspond with the
four plans of structure in animals, which Cuvier distin-
guished on the ground of comparative anatomy. Thus, for
example, the individual development of all Vertebrate
animals agrees, from the commencement, so much in its
fundamental features that the germs or embryos of different
Vertebrate animals (for example, of reptiles, birds, and
mammals) in their earlier stages cannot be distinguished at
all. It is only at a late stage of development that there
gradually appear the more marked differences of form which
separate those different classes and orders from one another.
In like manner the plan of structure, which shows itself in
the individual development of Articulate animals (insects,
spiders, crabs), is from the beginning essentially the same
in all Articulate animals, but different from that of all
Vertebrate animals. The same holds good, with certain
limitations, in Molluscous and Radiated animals.

Neither Bar, who arrived at the distinction of the four
animal types or principal forms through the history of the
individual development (Embryology), nor Cuvier, who

56 THE HISTORY OF CREATION.

arrived at the same conclusion by means of comparative
anatomy, recognized the true cause of this difference.
This is disclosed to us by the Theory of Descent. The
wonderful and astonishing similarity in the inner organi-
zation and in the anatomical relations of structure, and
the still more remarkable agreement in the embryonic de-
velopment of all animals belonging to one and the same
type (for example, to the branch of the Vertebrate animals),
is explained in the simplest manner by the supposition of
their common descent from a single primary original form.
If this view is not accepted, then the complete agreement of
the most different Vertebrate animals, in their inner struc-
ture and their manner of development, remains perfectly
inexplicable. In fact it can only be explained by the law of
inheritance.

Next to the comparative anatomy of animals and the
systematic zoology founded anew by it, it was specially to
the science of petrifactions, or Palaeontology, that Cuvier
rendered great service. We must draw special attention
to this, because these very palseontological views, and the
geological ideas connected with them, were held almost
universally in the highest esteem during the first half of
the present century, and caused the greatest hindrance to
the working out of a truly natural history of creation.

Petrifactions, the scientific study of which Cuvier pro-
moted at the beginning of our century in a most extensive
manner, and established quite anew for the Vertebrate
animals, play one of the most important parts in the " non-
miraculous history of creation." For these remains and
impressions of extinct animals and plants, preserved to us
in a petrified condition, are the true " monuments of the

FOSSIL ORGANISMS. 57

creation," the infallible and indisputable records which fix
the correct history of organisms upon an irrefragable founda-
tion. All petrified or fossil remains and impressions tell us
of the forms and structure of such animals and plants as are
either the progenitors and ancestors of the present living
organisms, or they are the representatives of extinct colla-
teral lines, which, together with the present living organisms,
branched off from a common stem.

These inestimable records of the history of creation
throughout a long period played a subordinate part in
science. Their true nature was indeed correctly understood,
even more than five hundred years before Christ, by the
great Greek philosopher, Xenophanes of Colophon, the same
who founded the so-called Eleatic philosophy, and who was
the first to demonstrate with convincing precision that all
conceptions of personal gods result in more or less rude
anthropomorphism.

Xenophanes for the first time asserted that the fossil im-
pressions of animals and plants were real remains of formerly
living creatures, and that the mountains in whose rocks
they were found must at an earlier date have stood under
water. But although other great philosophers of antiquity,
and among them Aristotle, also possessed this true know-
ledge, yet throughout the illiterate Middle Ages, and even
with some naturalists of the last century, the idea prevailed
that petrifactions were so-called freaks of nature (lusus
naturae), or products of an unknown formative power or
instinct of nature (nisus formativus, vis plastica). Respect-
ing the nature of this mysterious and mystic creative
power, the strangest ideas were formed. Some believed
tha,t this constructive power — the same to which they also

58 THE HISTORY OF CREATION.

ascribed the coming into existence of the present species of
animals and plants — had made numerous attempts to create
organisms of different forms, but that these attempts had
only partially succeeded, had often failed, and that petrifac-
tions were nothing more than such unsuccessful attempts.
According to others, petrifactions originated from the in-
fluence of the stars upon the interior of the earth.

Others, again, had the still cruder notion that the Creator
had first made models (out of mineral substances — for
example, of gypsum or clay) of those forms of animals and
plants which he afterwards executed in organic substances,
and into which he breathed his living breath ; petrifactions
were thus rude inorganic models. Even as late as the last
century these crude ideas prevailed, and it was assumed,
for example, that there existed a special "seminal air,"
which was said to penetrate into the earth with the water,
and by fructifying the stones formed petrifactions or "stony
flesh " (caro fossilis).

It took a very long time before the simple and natural
view was accepted, namely, that petrifactions are in reality
nothing but what they appear to simple observation — the
indestructible remains of extinct organisms. It is true the
celebrated painter, Leonardo da Vinci, in the 15th century,
ventured to assert that the mud which was constantly
deposited by water was the cause of petrifactions, as it
surrounded the indestructible shells of mussels and snails
which lay at the bottom of the waters, and gradually turned
them into solid stone. The same idea was maintained in
the 16th century by a Parisian potter, Palissy by name,
who became celebrated on account of his invention of china.
However, the so-called " professional men " were very far

OUVIEE'S WOEK IN PALAEONTOLOGY. 59

from paying any regard to these correct assertions of a
simple and healthy human understanding ; it was not till
the end of the last century that it was generally accepted,
in consequence of the foundation of the Neptunian geology
by Werner.

The foundation of a more strictly scientific palaeontology,
however, belongs to the beginning of our century, when
Cuvier published his classic researches on petrified Verte-
brate animals, and when his great opponent, Lamarck, made
known his remarkable investigations on fossil Invertebrate
animals, especially on petrified snails and clams. In Cuvier's
celebrated work " On the Fossil Bones " of Vertebrate animals
— principally of mammals and reptiles — we see that he had
already arrived at the knowledge of some very important
and general palaeontological laws, which are of great con-
sequence to the history of creation. Foremost among them
is his assertion that the extinct species of animals, whose
remains we find petrified in the different strata of the
earth's crust, lying one above another, differ all the more
strikingly from the still living kindred species of animals
the deeper those strata lie— in other words, the earlier the
animals lived in past ages. In fact, in every perpendicular
section of the stratified crust of the earth we find that the
different strata, deposited by the water in a certain historical
succession, are characterized by different petrifactions, and
that these extinct organisms become more like those of the
present day the higher the strata lie ; in other words, the
more recent the period in the earth's history in which they
lived, died, and became encrusted by the deposited and
hardened strata of mud.

However important this general observation of Cuvier's

60 THE HISTOEY OF CREATION.

was in one sense, yet in another it became to him the source
of a very serious error. For as he considered the charac-
teristic petrifactions of each individual group of strata
(which had been deposited during one main period of the
earth's history) to be entirely different from those of the
strata lying above or below, and as he erroneously believed
that one and the same species of animal was never found in
two succeeding groups of strata, he arrived at the false idea,
which was accepted as a law by most subsequent naturalists,
that a series of quite distinct periods of creation had
succeeded one another. Each period was supposed to have
had its special animal and vegetable world, each its peculiar
specific Fauna and Flora.

Cuvier imagined that the whole history of the earth's
crust, since the time when living creatures had first appeared
on the surface, must be divided into a number of perfectly
distinct periods, or divisions of time, and that the individual
periods must have been separated from one another by
peculiar revolutions of an unknown nature (cataclysms, or
catastrophes). Each revolution was followed by the utter
annihilation of the till then existing animals and plants,
and after its termination a completely new creation of
organic forms took place. A new world of animals and
plants, absolutely and specifically distinct from those of the
preceding historical periods, was called into existence at
once, and now again peopled the globe for thousands of
years, till it again was suddenly destroyed in the crash of
a new revolution.

As to the nature and causes of these revolutions, Cuvier
expressly states that no idea could be formed of them, and
that the present active forces in nature were not sufficient

CUVIEE'S CATACLYSMS. 6 1

for their explanation. Cuvier points out four active causes
as the natural forces, or mechanical agents, which were
constantly but slowly at work in changing the earth's
surface : first, rain, which washes down the steep mountain
slopes and heaps up debris at their foot ; secondly, flowing
waters, which carry away this debris and deposit it as mud
in stagnant waters ; thirdly, the sea, whose breakers gnaw
at the steep sea coasts, and throw up " dunes " on the flat
sea margins; finally and fourthly, volcanoes, which break
through and heave up the strata of the earth's hardened
crust, and pile up and scatter about the products of their
eruptions. Whilst Cuvier recognizes the constant slow
transformation of the present surface of the earth by these
four mighty causes, he asserts at the same time that they
would not have sufficed to effect the revolutions of the
remote ages, and that the anatomical structure of the
earth's surface cannot be explained by the necessary action
of those mechanical agents: the great and marvellous
revolutions of the whole earth's surface must, according to
him, have been rather the effects of very peculiar causes,
completely unknown to us ; the usual thread of development
was broken by them, and the course of nature altered.

These views Cuvier explained in a special work " On the
Revolutions of the Earth's Surface, and the Changes which
they have wrought in the Animal World." They were
maintained, and generally accepted for a long time, and
became the greatest obstacle to the development of a natural
history of the creation. For if such all-destructive revolu-
tions had actually occurred, of course a continuity of the
development of species, a connecting thread in the organic
history of the earth, could not be admitted at all, and we

62 THE HISTORY OP CREATION.

should be obliged to have recourse to the action of super-
natural forces ; that is, to the interference of miracles in the
natural course of things. It is only through miracles that
these revolutions of the earth could have been brought
about, and it is only through miracles that, after their
cessation and at the commencement of each new period, a
new animal and vegetable kingdom could have been created.
But science has no room for miracles, for by miracles we
understand an interference of supernatural forces in the
natural course of development of matter.

Just as the great authority which Linnaeus gained by
his system of distinguishing and naming organic species led
his successors to a complete ossification, as it were, of the
dogmatic ideas of species and to a real abuse of the syste-
matic distinction implied by it, so the great services which
Cuvier had rendered to the knowledge and distinction
of extinct species became the cause of a general adoption
of his theory of revolutions and catastrophes, and of the
false views of creation connected therewith. The conse-
quence of this was that, during the first half of our century,
most zoologists and botanists clung to the opinion that a
series of independent periods in the organic history of the
earth had existed; that each period was distinguished by
distinct and peculiar kinds of animal and vegetable species,
that these were annihilated at the termination of the period
by a general revolution ; and that, after the cessation of the
latter, a new world of different species of animals and plants
was created.

It is true some independent thinkers, above all the great
physical philosopher, Lamarck, even at an early period, set
forth a series of weighty reasons which refuted Cuvier's

AGASSIZ ON CREATION. 63

theory of cataclysms, and pointed to a perfectly continuous
and uninterrupted history in the development of all the
organic inhabitants of the earth through all ages. They
maintained that the animal and vegetable species of each
period were derived from those of the preceding period,
and were only the altered descendants of the former. This
true conception, however, being opposed to Cuvier's great
authority, was then unable to make way. Nay, even after
Cuvier's theory of catastrophes had been completely cast
out from the domain of geology by Lyell's classic " Principles
of Geology," which appeared in 1830, his idea of the specific
distinctness of a series of organic creations still, in many
ways, maintained its influence in the science of Palseontology
("Gen. Morph."ii. 312).

By a curious coincidence, thirty years ago, almost at the
same time that Cuvier's History of Creation received its
death-blow by Darwin's book, another celebrated naturalist
made an attempt to re-establish it, and to adopt it in the
crudest manner, as a part of a teleologico-theological system
of nature. This was the Swiss geologist, Louis Agassiz,
who attained a great reputation by his theory of glaciers
and the ice-period, borrowed from Schimper and Charpentier ;
he lived in North America for many years, and died there
in 1873. He commenced in 1858 to publish a work
planned on a very large scale, which bears the title of
" Contributions to the Natural History of the United States
of North America." The first volume of this work, although
large and costly, owing to the patriotism of the Americans,
had an unprecedented sale ; its title is, " An Essay on
Classification." 5

In this essay Agassiz not only discusses the natural series

64 THE HISTORY OP CREATION.

of organisms, and the different attempts of naturalists at
classification, but also all the general biological phenomena
which have reference to it. The history of the development
of organisms, both the embryonal and the palseontologieal,
comparative anatomy, the general economy of nature, the
geographical and topographical distribution of animals and
plants — in short, almost all the general phenomena of
organic nature are discussed in Agassiz's Essay on Classifi-
cation, and are explained in a sense and from a point of
view which is thoroughly opposed to that of Darwin.
While Darwin's chief merit lies in the fact that he demon-
strates natural causes for the coming into existence of
animal and vegetable species, and thereby establishes the
mechanical or monistic view of the universe as regards this
most difficult branch of the history of creation, Agassiz, on
the contrary, strives to exclude every mechanical hypothesis
from the subject, and to put the supernatural interference
of a personal Creator in the place of the natural forces of
matter; consequently, to establish a thoroughly teleological
or dualistic view of the universe. It will not be out of
place if I examine a little more closely Agassiz's biological
views, and especially his ideas of creation, because no other
work of our opponents treats the important fundamental
questions with equal minuteness, and because the utter
untenableness of the dualistic conception of nature becomes
very evident from the failure of this attempt.

The organic species, the various conceptions of which we
have above designated as the real centre of dispute in the
opposed views of creation, is looked upon by Agassiz, as
by Cuvier and Linnaeus, as a form unchangeable in all its
essential characteristics. The species may indeed change

AGASSIZ ON CBEATION. 65

and vary within certain narrow limits ; never in essential
qualities, but only in unessential points. No new species
could ever proceed from the changes or varieties of a species.
Not one of all organic species, therefore, is ever derived from
another, but each individual species has been separately
created by God. Each individual species, as Agassiz ex-
presses it, is " an embodied creative thought " of God.

In direct opposition to the fact established by palseonto-
logical experience, that the duration of the individual
organic species is most unequal, and that many species
continue unchanged through several successive periods of
the earth's history, while others only existed during a small
portion of such a period, Agassiz maintains that one and
the same species never occurs in two different periods, but
that each individual period is characterized by species of
animals and plants which are quite peculiar, and belong to
it exclusively. He further shares Cuvier's opinion that the
whole of these inhabitants were annihilated by the great
and universal revolutions of the earth's surface, which
divide two successive periods, and that after its destruction
a new and specifically different assemblage of organisms
was created. This new creation Agassiz supposes to have
taken place in this manner : viz., that at each creation all
the inhabitants of the earth, in their full average number
of individuals, and in the peculiar relations corresponding
to the economy of nature, were, as a whole, suddenly placed
upon the earth by the Creator. In saying this he puts
himself in opposition to one of the most firmly established
and most important laws of animal and vegetable geography
— namely, to the law that each species has a single original
locality of origin, or a so-called " centre of creation," from
vol. 1. F

66 THE HISTORY OF CREATION.

which it has gradually spread over the rest of the earth.
Instead of this, Agassiz assumes each species to have been
created at several points of the earth's surface, and that in
each case a large number of individuals was created.

The " natural system " of organisms, the different groups
and categories of which arranged above one another —
namely, the branches, classes, orders, families, genera, and
species — we consider, in accordance with the Theory of
Descent, as different branches and twigs of the organic
family-tree, is, according to Agassiz, the direct expression
of the divine plan of creation, and the naturalist, while
investigating the natural system, repeats the creative
thoughts of God. In this Agassiz finds the strongest proof
that man is the image and child of God. The different
stages of groups or categories of the natural system corre-
spond with the different stages of development which the
divine plan of creation had attained. The Creator, in pro-
jecting and carrying out this plan, and starting from the
most general ideas of creation, plunged more and more into
specialities. For instance, when creating the animal king-
dom, God had in the first place four totally distinct ideas of
animal bodies, which he embodied in the different structures
of the four great, principal forms, types, or branches of the
animal kingdom; namely, vertebrate animals, articulate
animals, molluscous animals, and radiate animals. The
Creator then, having reflected in what manner he might
vary these four different plans of structure, next created
within each of the four principal forms, several different
classes — for example, in the vertebrate animal form, the
classes of mammals, birds, reptiles, amphibious animals, and
fishes. Then God further reflected upon the individual

THE CREATOR AS AN ARCHITECT. 6j

classes, and by various modifications in the structure of
each class, he produced the individual orders. By further
variation in the order, he created natural families. As the
Creator further varied the peculiarities of structure of
individual parts in each family, genera arose. In further
meditation on his plan of creation, he entered so much into
detail that individual species came into existence, which,
consequently, are embodied creative thoughts of the most
special kind. It is only to be 'regretted that the Creator
expressed these most special and most deeply considered
" creative thoughts " in so very indistinct and loose a
manner, and that he imprinted so vague a stamp upon
them, and permitted them to vary so freely that not one
naturalist is able to distinguish the " good " from the " bad
species," or a genuine species from varieties, races, etc.

We see, then, according to Agassiz's conception, that the
Creator, in producing organic forms, goes to work exactly
as a human architect, who has taken upon himself the task
of devising and producing as many different buildings as
possible, for the most manifold purposes, in the most dif-
ferent styles, in various degrees of simplicity, splendour,
greatness, and perfection. This architect would perhaps at
first choose four different styles for all these buildings, say
the Gothic, Byzantine, Moorish, and Chinese styles. In
each of these styles he would build a number of churches,
palaces, garrisons, prisons, and dwelling-houses. Each of
these different buildings he would execute in ruder and
more perfect, in greater and smaller, in simpler and grander
fashion, etc. However, the human architect would perhaps,
in this respect, be better off than the divine Creator, as he
would have perfect liberty in the number of graduated

68 THE HISTORY OF CREATION.

subordinate groups. The Creator, however, according to
Agassiz, can move only within six groups or categories :
the species, genus, family, order, class, and type. More than
these six categories do not exist for him.

When we read Agassiz's book on classification, and see
how he carries out and establishes these strange ideas, we
can scarcely understand how, with all the appearances of
scientific earnestness, he could persevere in his idea of the
divine Creator as a man-like being (anthropomorphism), for
by his explanation of details he produces a picture of the
most absurd nonsense. In the whole series of these sup-
positions the Creator is nothing but an all-mighty man, who,
plagued with ennui, amuses himself with planning and
constructing all manner of toys in the shape of organic
species. After having diverted himself with these for
thousands of years, they become tiresome to him, he destroys
them by a general revolution of the earth's surface, and
thus throws the whole of the useless toys in heaps together ;
then, in order to while away his time with something new
and better, he calls a new and more perfect animal and
vegetable world into existence. But in order not to have
the trouble of beginning the work of creation over again,
he keeps, in the main, to his original plan of creation, and
creates merely new species, or at most only new genera,
much more rarely new families, new orders, or classes. He
never succeeds in producing a new style or type, and
always keeps strictly within the six categories or graduated
groups.

When, according to Agassiz, the Creator has thus amused
himself for thousands of millions of years with constructing
and destroying a series of different creations, at last (but

INCONSISTENCY OF AGASSIZ.' 6g

very late) he is struck with the happy thought of creating
something like himself, and so makes man in his own image.
With this, the aim of all the history of creation is arrived
at and the series of revolutions of the earth is closed. Man,
the child and image of God, gives him so much to do, causes
him so much pleasure and trouble, that he is wearied no
longer, and therefore need not undertake a new creation.
It is clear that if, according to Agassiz, we once assign to
the Creator entirely human attributes and qualities, and
regard his work of creation as entirely analogous to human
creative activity, we are necessarily obliged to admit such
utterly absurd inferences as those just stated.

The many intrinsic contradictions and perversities in
Agassiz's view of creation — a view which necessarily led
him to the most decided opposition to the Theory of Descent
— must excite our astonishment all the more because, in his
earlier scientific works, he has in many respects actually
paved the way for Darwin, especially by his researches in
Palaeontology. Among the numerous investigations which
created general interest in the then young science of
Palaeontology, those of Agassiz, especially his celebrated
work on " Fossil Fish," rank next in importance to Cuvier's
work, which formed the foundation of the science. The
petrified fish, with which Agassiz has made us acquainted,
have not only an extremely great importance for the under-
standing of all groups of Vertebrate animals, and their
historical development, but we have arrived through them
at a sure knowledge of important general laws- of develop-
ment. It was Agassiz who drew special attention to the
remarkable parallelism between the embryonal and the
palseontological development — between ontogeny and phy-

70, THE HISTORY OF CREATION.

lpgeny, which 'I have already (p. 10) claimed as one of the
strongest pillars of the Theory of Descent. No one before
had so distinctly stated as Agassiz did, that, of the Verte-
brate animals, fishes alone existed at first, that amphibious
animals came later, and that birds and mammals appeared
only at a much later period ; further, that among mammals,
as among fishes, imperfect and lower orders had appeared
first, but more perfect and higher orders at a later period.
Agassiz, therefore, showed that the palaeontological develop-
ment of the whole Vertebrate group was not only parallel
With the embryonic, but also with the systematic develop-
ment, that is, with the graduated series which we see
everywhere in the system, ascending from the lower to the
higher classes, orders, etc.

' In the earth's history lower forms appeared first, the
higher forms later. This important fact, as well as the
agreement of the embryonic and palaeontological develop-
ment, is explained quite simply and naturally by the
Doctrine of Descent, and without it is perfectly inexplicable.
This cause holds good also in the great law of progressive
development, that is, of the historical progress of organiza-
tion, which is traceable, broadly and as a whole, in the
historical succession of all organisms, as well as in the
special perfecting of individual parts of animal bodies.
Thus, for example, the skeleton of Vertebrate animals
acquired at first slowly, and by degrees, that high degree
of perfection which it now possesses in man and the other-
higher Vertebrate animals. This progress acknowledged in
point of fact by Agassiz, necessarily follows from Darwin's
Doctrine of Descent, which demonstrates its active causes.
If this doctrine is correct, the perfecting and diversification

DEVELOPMENT OF THE CREATOR. 7 1

of animal and vegetable species must of necessity have
gradually increased in the course of the organic history of
the earth, and could only attain its highest perfection in
most recent times.

The above-mentioned laws of development, together with
some other general ones, which have been expressly admitted
and justly emphasized by Agassiz, and some of which have
first been set forth by him, are, as we shall see later, only
explicable by the Theory of Descent, and without it remain
perfectly incomprehensible. The conjoint action of In-
heritance and Adaptation, as explained by Darwin, can
alone be their true cause. But they all stand in sharp and
irreconcilable opposition to the hypothesis of creation main-
tained by Agassiz, as well as to the idea of a personal
Creator who acts for a definite purpose. If we seriously
wish to explain those remarkable phenomena and their
inner connection by Agassiz's theory, then we are necessarily
driven to the supposition that the Creator himself has
developed, together with the organic nature which he
created and modelled. We can, in that case, no longer rid
ourselves of the idea that the Creator himself, like a human
being, designed, improved, and finally, with many altera-
tions, carried out his plans. " Man grows as higher grow
his aims," says the poet, and this remark, so unworthy of a
God, must be applied to him. Although, from the reverence
with which, in every page, Agassiz speaks of the Creator, it
might appear that, by his theory, we attain to the sublimest
conception of the divine activity in nature, yet the contrary
is in truth the case. The divine Creator is degraded to the
level of an idealized man, of an organism progressing in
development. According to this low conception God is, in
fact, nothing more than a " gaseous vertebrate."

72 THE HISTORY OF CREATION.

Considering the wide popularity and great authority
which Agassiz's work has gained, and which is perhaps
justified on account of earlier scientific services rendered by
the author, I have thought it my duty here to show the
utter untenableness of his general conceptions. So far as
his work pretends to be a scientific history of creation, it is
undoubtedly a complete failure. But still it is of great
value, in being the only detailed attempt, adorned with
scientific arguments, which an eminent naturalist of our
day has made to found a teleological or dualistic history of
creation. The utter impossibility of such a history has thus
been made obvious to every one. No opponent of Agassiz
could have refuted the dualistic conception of organic nature
and its origin more strikingly than he himself has done by
the intrinsic contradictions which present themselves every-
where in his theory.

The opponents of the monistic or mechanical conception
of the world have welcomed Agassiz's work with delight,
and find in it a perfect proof of the direct creative action of
a personal God. But they overlook the fact that this per-
sonal Creator is only an idealized organism, endowed with
human attributes. This low dualistic conception of God is
in keeping with a lower animal stage of development of the
human organism. The more developed man of the present
day is capable of, and justified in, conceiving that infinitely
nobler and sublimer idea of God which alone is compatible
with the monistic conception of the universe, and which
recognizes God's spirit and power in all phenomena without
exception. This monistic idea of God, which belongs to the
future, has already been expressed by Giordano Bruno in
the following words : " A spirit exists in all things, and no

UNITY OF GOD AND NATURE. 73

body is so small but contains a part of the divine substance
within itself, by which it is animated." This sublime con-
ception of God is based upon the religion within the sphere
of which the noblest minds of antiquity as well as of
modern times have thought and lived, viz. Pantheism. It
is of this noble idea of God that Goethe says : " Certainly
there does not exist a more beautiful worship of God than
that which needs no image, but which arises in our heart
from converse with Nature." By it we arrive at the
sublime, pantheistic idea of the Unity of God and Nature.

74 THE HISTORY OF CREATION.

CHAPTER IV.

THEORY OF DEVELOPMENT ACCORDING TO GOETHE
AND OKEN.

Scientific Insufficiency of all Conceptions of a Creation of Individual Species.
— Necessity of the Counter- Theories of Development. — Historical
Survey of the Most Important Theories of Development. — Greek
Philosophy. — The Meaning of Natural Philosophy. — Goethe. — His
Merits as a Naturalist. — His Metamorphosis of Plants. — His Vertebral
Theory of the Skull. — His Discovery of the Mid Jawbone in Man. —
Goethe's Interest in the Dispute between Cuvier and Geoffroy St.
Hilaire. — Goethe's Discovery of the Two Organic Formative Principles,
of the Conservative Principle of Specification (by Inheritance), and
of the Progressive Principle of Transformation (by Adaptation). —
Goethe's Views of the Common Descent of all Vertebrate Animals,
including Man. — Theory of Development according to Gottfried Rein-
hold Treviranus. — His Monistic Conception of Nature. — Oken. — Hia
Natural Philosophy. — Oken's Theory of Protoplasm. — Oken's Theory
of Infusoria (Cell Theory).

All the different ideas which we may form of a separate
and independent origin of the individual organic species
by creation lead us, when logically carried out, to a so-
called anthropomorphism, that is, to imagining the Creator
as a man-like being, as was shown in our last chapter.
The Creator becomes an organism who designs a plan,
reflects upon, and varies this plan, and finally forms
creatures according to this plan, as a human architect

FAILURE OF TELEOLOGY. J$

would his building. If even such eminent naturalists as
Linnaeus, Ouvier, and Agassiz, the principal representatives
of the dualistic hypothesis of creation, could not arrive at
a more satisfactory view, we may take it as evidence of the
insufficiency of all those conceptions which would derive
the various forms of organic nature from a creation of
individual species.

Some naturalists, indeed, seeing the complete insuffi-
ciency of these views, have tried to replace the idea of a
personal Creator by that of an unconsciously active and
creative Force of Nature ; yet this expression is evidently
merely an evasive phrase, as long as it is not clearly shown
what this force of nature is, and how it works. Hence
these attempts, also, are of no value whatever to science.
In fact, whenever an independent origin of the different
forms of animals and plants has been assumed, naturalists
have found themselves compelled to fall back upon so many
"acts of creation," that is, on supernatural interferences of
the Creator in the natural course of things, which in all
other cases goes on without interference.

It is true that several teleological naturalists, feeling
the scientific insufficiency of a supernatural " creation,"
have endeavoured to save the hypothesis by wishing it to
be understood that creation " is nothing else than a way of
coming into being, unknown and inconceivable to us." The
eminent Fritz Muller has cut off from this sophistic evasion
every chance of escape by the following striking remark :
" It is intended here only to express in a disguised manner
the shamefaced confession, that they neither have, nor care
to have, any opinion about the origin of species. Accord-
ing to this explanation of the word, we might as well speak

76 THE HISTOBY OF CREATION.

of the creation of cholera, or syphilis, of the creation of a
conflagration, or of a railway accident, as of the creation of
man " (" Jenaische Zeitschrift," bd. v. p. 272).

In the face, then, of these hypotheses of creation, which
are scientifically insufficient, we are forced to seek refuge in
the counter-theory of development of organisms, if we wish
to come to a rational conception of the origin of organisms.
We are forced and obliged to do so, even if the theory of
development only throws a glimmer of probability upon a
mechanical, natural origin of the animal and vegetable
species; but all the more if, as we shall see, this theory
explains all facts simply and clearly, as well as completely
and comprehensively. The theories of development are by
no means, as they often falsely are represented to be,
arbitrary fancies, or wilful products of the imagination,
which only attempt approximately to explain the origin of
this or that individual organism; but they are theories
founded strictly on science, which explain in the simplest
manner, from a fixed and clear point of view, the whole of
organic natural phenomena, and more especially the origin
of organic species, and demonstrate them to be the necessary
consequences of mechanical processes in nature.

As I have already shown in the second chapter, all these
theories of development coincide naturally with that general
theory of the universe which is usually designated as the
uniform or monistic, often also as the mechanical or causal,
because it only assumes mechanical causes, or causes work-
ing by necessity (causae efficientes), for the explanation of
natural phenomena. In like manner, on the other hand,
the supernatural hypotheses of creation which we have
already discussed coincide completely with the opposite

THE THEORY OF DESCENT. 77

view of the universe, which in contrast to the former is
called the twofold or dualistic, often the teleological or vital,
because it traces the organic natural phenomena to final
causes, acting and working for a definite purpose (causae
finales). It is this deep and intrinsic connection of the
different theories of creation with the most important
questions of philosophy that incites us to their closer
examination.

The fundamental idea, which must necessarily lie at the
bottom of all natural theories of development, is that of
a gradual development of all (even the most perfect) or-
ganisms out of a single, or out of a very few, quite simple,
and quite imperfect original beings, which came into exist-
ence, not by supernatural creation, but by spontaneous
generation, or archigony, out of inorganic matter. In
reality, there are two distinct conceptions united in this
fundamental idea, but which have, nevertheless, a deep in-
trinsic connection — namely, first, the idea of spontaneous
generation (or archigony) of the original primary beings ;
and secondly, the idea of the progressive development of
the various species of organisms from those most simple
primary beings. These two important mechanical concep-
tions are the inseparable fundamental ideas of every theory
of development, if scientifically carried out. As it maintains
the derivation of the different species of animals and plants
from the simplest, common primary species, we may term it
also the Doctrine of Filiation, or Theory of Descent ; as there
is also a change of species connected with it, it may also be
termed the Transmutation Theory.

While the supernatural histories of creation must have
originated thousands of years ago, in that very remote

78 THE HISTORY OF CEEATION.

primitive age when man, first developing out of the monkey-
state, began for the first time to think more closely about
himself, and about the origin of the world around him, the
natural theories of development, on the other hand, are
necessarily of much more recent origin. These views are
met with only among nations of a more matured civiliza-
tion, to whom, by philosophic culture, the necessity of a
knowledge of natural causes has become apparent; and
even among these, only individual and specially gifted
natures can be expected to have recognized the origin of
the world of phenomena, as well as its course of development,
as the necessary consequences of mechanical, naturally active
causes. In no nation have these preliminary conditions, for
the origin of a natural theory of development, ever existed
in so high a degree as among the Greeks of classic antiquity.
But, on the other hand, they lacked a close acquaintance
with the facts of the processes and forms of nature, and,
consequently, the foundation based upon experience, for a
satisfactory unravelling of the problem of development.
Exact investigation of nature, and the knowledge of nature
founded on an experimental basis, was of course almost
unknown to antiquity, as well as to the Middle Ages, and
is only an acquisition of modern times. We have therefore
here no special occasion to examine the natural theories of
development of the various Greek philosophers, since they
were wanting in the knowledge gained by experience, both
of organic and inorganic nature.

We will here mention only that as early as the seventh
century before Christ, the representatives of the Ionian
philosophy of nature, Thales, Anaximenes, and Anaximander
of Melitus, and more especially Anaximander, established

ARISTOTLE ON THE ORIGIN OF LIFE. 79

important principles of our modern monism. Their teaching
pointed to a uniform law of nature as the basis of the
various phenomena, a unity of all nature and a continual
change of forms. Anaximander considered that the animal-
cules in water came into existence through the influence of
the warmth of the sun, and assumed that man had developed
out of fish-like ancestors. At a later date also, we find in
the natural philosophy of Heraclitus and Empedocles, as
well as in the writings of Democritus and Aristotle, many
allusions to conceptions which we regard as the fundamental
supports of our modern theory of development. Empedocles
points out that things which appear to have been made for
a definite purpose may have arisen out of what had no
purpose whatever. Aristotle assumes spontaneous genera-
tion as the natural manner in which the lower organisms
came into existence ; for instance he supposes moths to pro-
ceed from wool, fleas from putrid dung, wood-lice from
damp wood, etc.

The fundamental notion of the theory of development,
that the different species of animals and plants have been
developed from a common primary species by transformation,
could of course only be clearly asserted after the kinds or
species themselves had become better known, and after the
extinct species had been carefully examined and compared
with the living ones. This was not done until the end of
the last and the beginning of the present century. It was
not until the year 1801 that the great Lamarck expressed
the theory of development, which he, in 1809, further
elaborated in his classical " Philosophie Zoologique." And
while Lamarck and his countryman, Geoffroy St. Hilaire, in
France, opposed Cuvier's views, and maintained a natural

80 THE HISTORY OF CREATION.

development of organic species by transformation and
descent, Goethe and Oken pursued the same course in
Germany, and helped to establish the theory of develop-
ment. As these naturalists are generally called nature-
philosophers (Natur-philosophen), and as this ambiguous
designation is correct in a certain sense, it appears to me
appropriate here to say a few words about the correct
estimate of the " Natur-philosophie."

Although for many years in England the ideas of natural
science and philosophy have been looked upon as almost
equivalent, and every truly scientific investigator of
nature is most justly called there a " natural philosopher,"
yet in Germany for more than half a century natural science
has been kept strictly distinct from philosophy, and the
union of the two into a true philosophy of nature is recog-
nized only by the few. This misapprehension is owing
to the fantastic eccentricities of earlier German natural-
philosophers, such as Oken, Schelling, etc. ; they believed
that they were able to construct the laws of nature in their
own heads, without being obliged to take their stand upon
the grounds of actual experience. When the complete
hollo wness of their assumptions had been demonstrated,
naturalists, in " the nation of thinkers," fell into the very
opposite extreme, believing that they would be able to
reach the high aim of science, that is, the knowledge of
truth, by the mere experience of the senses, and without
any philosophical activity of thought.

From that time, but especially since 1830, most naturalists
have shown a strong aversion to any general, philosophical
view of nature. The real aim of natural science was now
supposed to consist in the knowledge of details, and it was

OBSERVATION AND REFLECTION. 8 1

believed that this would be attained in the study of biology,
when the forms and the phenomena of life, in all individual
organisms, had become accurately known, by the help of the
finest instruments and means of observation. It is true that
among these strictly empirical, or so-called exact naturalists,
there were always very many who rose above this narrow
point of view, and sought the final aim in a knowledge of
the general laws of organization. Yet the great majority of
zoologists and botanists, during the thirty or forty years
preceding Darwin, refused to concern themselves about such
general laws ; all they admitted was, that perhaps in the far
distant future, when the end of all empiric knowledge should
have been arrived at, when all individual animals and plants
should have been thoroughly examined, naturalists might
begin to think of discovering general biological laws.

If we consider and compare the most important advances
which the human mind has made in the knowledge of
truth, we shall soon see that it is always owing to philo-
sophical mental operations that these advances have been
made, and that the experience of the senses which certainly
and necessarily precedes these operations, and the knowledge
of details gained thereby, only furnish the basis for those
general laws. Experience and philosophy, therefore, by no
means stand in such exclusive opposition to each other as
most men have hitherto supposed ; they rather necessarily
supplement each other. The philosopher who is wanting in
the firm foundation of sensuous experience, of empirical
knowledge, is very apt to arrive at false conclusions in his
general speculations, which even a moderately informed
naturalist can refute at once. On the other hand, the purely
empiric naturalists, who do not trouble themselves about the

VOL. I. G

82 THE HISTORY OF CREATION.

philosophical comprehension of their sensuous experiences
and who do not strive after general knowledge, can promote
science only in a very slight degree, and the chief value of
their hard-won knowledge of details lies in the general
results which more comprehensive minds will one day
derive from them.

From a general survey of the course of biological develop-
ment since Linnaeus' time, we can easily see, as Bar has
pointed out, a continual vacillation between these two ten-
dencies, at one time a prevalence of the empirical — the
so-called exact — and then again of the philosophical or
speculative tendency. Thus at the end of the last century,
in opposition to Linnaeus' purely empirical school, a natural-
philosophical reaction took place, the moving spirits of
which, Lamarck, Geoffroy St. Hilaire, Goethe, and Oken,
endeavoured by their mental work to introduce light and
order into the chaos of the accumulated empirical raw
material. In opposition to the many errors and specula-
tions of these natural philosophers, who went too far,
Cuvier then came forward, introducing a second, purely
empirical period. It reached its most one-sided development
between the years 1830-1860, and there now followed a
second philosophical reaction, caused by Darwin's work.
Thus during the last thirty years, men again have begun to
endeavour to obtain a knowledge of the general laws of
nature, to which, after all, all detailed knowledge of experi-
ence serves only as a foundation, and through which alone
it acquires its true value. It is through philosophy alone
that natural knowledge becomes a true science, that is, a
philosophy of nature.

Jean Lamarck and Wolfgang Goethe stand at the head of

GOETHE AS A NATURALIST. 83

all the great philosophers of nature who first established a
theory of organic development, and who are the illustrious
fellow- workers of Darwin. I turn first to the incomparable
Goethe, who, above all, stands closest to us Germans. How-
ever, before I explain his special services to the theory of
development, it seems to me necessary to say a few words
about his importance as a naturalist in general, as it is
commonly very little known.

I am sure most of my readers honour Goethe only as a
poet and a man ; only a few have any conception of the
high value of his scientific works, and of the gigantic stride
with which he advanced before his own age — advanced so
much that most naturalists of that time were unable to
follow him. In several passages of his scientific writings
he bitterly complains of the narrow-mindedness of professed
naturalists, who did not know how to value his works
(who could not see the forest for the trees), and who could
not rouse themselves to discover the general laws of nature
among the mass of details. He is only too just when he
utters the reproach — " Philosophers will very soon discover
that observers rarely rise to a standpoint from which they
can survey so many important objects." It is true, at the
same time, that their want of appreciation was caused by
the false road into which Goethe was led in his theory of
colours.

This theory of colours, which he himself designates as
the favourite production of his leisure, however much that
is beautiful it may contain, is a complete failure in regard
to its foundations. The exact mathematical method by
means of which alone it is possible, in inorganic sciences,
but above all in physics, to raise a structure step by step

84 THE HISTOEY OF CREATION.

on a thoroughly firm basis, was altogether repugnant to
Goethe. In rejecting it he allowed himself not only to be
very unjust towards the most eminent physicists, but to be
led into errors which have greatly injured the fame of his
other valuable works. It is quite different in the organic
sciences, in which we are but rarely able to proceed, from
the beginning, upon a firm mathematical basis; we are
rather compelled, by the infinitely difficult and intricate
nature of the problem, at the first to form inductions — that
is, we are obliged to endeavour to establish general laws
by numerous individual observations, which are not quite
complete. A comparison of kindred series of phenomena,
or the method of combination, is here the most important
instrument for inquiry, and this method was applied by
Goethe with as much success as with conscious knowledge
of its value, in his works relating to the philosophy of
nature.

The most celebrated among Goethe's writings relating to
organic nature is his "Metamorphosis of Plants," which
appeared in 1790, a work which distinctly shows a grasp of
the fundamental idea of the theory of development, inasmuch
as Goethe, in it, was labouring to point out a single organ,
by the infinitely varied development and metamorphosis of
which the whole of the endless variety of forms in the
world of plants might be conceived to have arisen; this
fundamental organ he found in the leaf. If the microscope
had then been generally employed, if Goethe had examined
the structure of organisms by the means of the microscope,
he would have gone still further, and would have seen that
the leaf is itself a compound of individual parts of a lower
order, that is, of cells. He would then not have declared

GOETHE'S THEORY OF THE SKULL. 85

that the leaf, but that the cell is the real fundamental organ
by the multiplication, transformation, and combination
(synthesis) of which, in the first place, the leaf is formed ;
and that, in the next place, by transformation, variation,
and combination of leaves there arise all the varied beauties
in form and colour which we admire in the green parts, as
well as in the organs of propagation, or the flowers of
plants. But nevertheless his fundamental idea was per-
fectly correct. Goethe there showed that in order to com-
prehend the whole of the phenomena, we must in the first
place compare them, and, secondly, search for a simple type,
a simple fundamental form, of which all other forms are
only infinite variations.

Something similar to what he had here done for the
metamorphosis of plants he then did for the Vertebrate
animals, in his celebrated vertebral theory of the skull.
Goethe was the first to show, independently of Oken, who
almost simultaneously arrived at the same thought, that
the skull of man and of all Vertebrate animals, particularly
of mammals, is merely a transformed portion of the topmost
piece of the vertebral column. The vertebrae of the skull
are like those of the spine, bony rings lying behind each
other, but in the skull are peculiarly changed and specialized
(differentiated). Although this idea has, of late years, been
greatly modified by Gegenbauer's astute investigations, yet
in Goethe's day it was one of the greatest advances in com-
parative anatomy, and was not only one of the first
advances towards the understanding of the structure of
Vertebrate animals, but at the same time explained many
individual phenomena. When two parts of a bod}-, such as
the skull and spine, which appear at first sight so different,

86 THE HISTORY OF CREATION.

were proved to be parts originally the same, developed out
of one and the same foundation, one of the difficult problems
of the philosophy of nature was solved. Here again we
meet the notion of a single type — the conception of a single
principle, which becomes infinitely varied in the different
species, and in the parts of individual species.

But Goethe did not merely endeavour to search for such
far-reaching laws, he also occupied himself most actively
for a long time with numerous individual researches,
especially in comparative anatomy. Among these, none is
perhaps more interesting than the discovery of the midjaiv-
bone in man. As this is, in several respects, of importance
to the theory of development, I shall briefly explain it here.
There exist in all mammals two little bones in the upper
jaw, which meet in the centre of the face, below the nose,
and which lie between the two halves of the real upper
jawbone. These two bones, which hold the four upper
cutting teeth, are recognized without difficulty in most
mammals; in man, however, they were at that time un-
known, and celebrated comparative anatomists even laid
great stress upon this want of a mid jawbone, as they con-
sidered it to constitute the principal difference between
men and apes — the want of a mid jawbone was, curiously
enough, looked upon as the most human of all human
characteristics. But Goethe could not accept the notion
that man, who in all other corporeal respects was clearly
only a mammal of higher development, should lack this
mid jawbone.

By the general law of induction as to the mid jawbone
he arrived at the special deductive conclusion that it must
exist in man also, and Goethe did not rest until, after com-

THEORY OF THE SKULL. 87

paring a great number of human skulls, he really found the
mid jawbone. In some individuals it is preserved throughout
a whole lifetime, but usually at an early age it coalesces
with the neighbouring upper jawbone, and is therefore only
to be found as an independent bone in very youthful skulls.
In human embryos it can now be pointed out at any
moment. In man, therefore, the mid jawbone actually
exists, and to Goethe the honour is due of having first
firmly established this fact, so important in many respects ;
and this he did while opposed by the celebrated anatomist,
Peter Camper, one of the most important professional
authorities. The way by which Goethe succeeded in estab-
lishing this fact is especially interesting ; it is the way by
which we continually advance in biological science, namely,
by way of induction and deduction. Induction is the
inference of a general law from the observation of numerous
individual cases; deduction, on the other hand, is an
inference from this general law applied to a single case
which has not yet been actually observed. From the col-
lected empirical knowledge of those days, the inductive
conclusion was arrived at that all mammals had mid jaw-
bones. Goethe drew from this the deductive conclusion,
that man, whose organization was in all other respects not
essentially different from mammals, must also possess this
mid jawbone; and on close examination it was actually
found. The deductive conclusion was confirmed and verified
by experience.

Even these few remarks may serve to show the great
value which we must ascribe to Goethe's biological re-
searches. Unfortunately, most of his labours devoted to
this subject are so hidden in his collected works, and his

88 THE HISTORY OF CREATION.

most important observations and remarks so scattered in
numerous individual treatises — devoted to other subjects —
that it is difficult to find them out. It also sometimes
happens that an excellent, truly scientific remark is so
much interwoven with a mass of useless philosophical
fancies, that the latter greatly detract from the former.

Nothing is perhaps more characteristic of the extra-
ordinary interest which Goethe took in the investigation
of organic nature than the lively way in which, even in his
last years, he followed the dispute which broke out in
France between Cuvier and Geoffroy de St. Hilaire. Goethe,
in a special treatise which was only finished a few days
before his death, in March, 1832, has given an interesting
description of this remarkable dispute and its general im-
portance, as well as an excellent sketch of the two great
opponents. This treatise bears the title, "Principes de
Philosophie Zoologique par M. Geoffroy de Saint Hilaire ; "
it is Goethe's last work, and forms the conclusion of the
collected edition of his works. The dispute itself was, in
several respects, of the highest interest. It turned essentially
upon the justification of the theory of development. It
was carried on, moreover, in the bosom of the French
Academy, by both opponents, with a personal vehemence
almost unheard of in the dignified sessions of that learned
body ; this proved that both naturalists were fighting for
their most sacred and deepest convictions. The conflict
began on the 22nd of February, and was followed by
several others ; the fiercest took place on the 19th of
July, 1830. Geoffroy, as the chief of the French nature-
philosophers, represented the theory of natural development
and the monistic conception of nature. He maintained the

GOETHE AND ST. HILAIRE. 89

mutability of organic species, the common descent of the
individual species from common primary forms, and the
unity of their organization — or the unity of the plan of
structure, as it was then called.

Cuvier was the most decided opponent of these views,
and, according to what we have seen, it could not be
otherwise. He endeavoured to show that the nature-
philosophers had no right to rear such comprehensive con-
clusions on the basis of the empirical knowledge then
possessed, and that the unity of organization — or plan of
structure of organisms — as maintained by them, did not
exist. He represented the teleological (dualistic) conception
of nature, and maintained that " the immutability of species
was a necessary condition for the existence of a scientific
history of nature." Cuvier had the great advantage over
his opponent, that he was able to bring towards the proof
of his assertions things obvious to the eye ; these, however,
were only individual facts taken out of their connection
with others. Geoffrey was not able to prove the higher
and general connection of individual phenomena which he
maintained, by equally tangible details. Hence Cuvier, in
the eyes of the majority, gained the victory, and decided
the defeat of the nature-philosophy and the supremacy of
the strictly empiric tendency.

Goethe of course supported Geoffrey's views. How deeply
interested he was, even in his 81st year, in this great contest
is proved by the following anecdote related by Soret : —

" Monday, Aug. 2nd, 1830. — The news of the outbreak of
the revolution of July arrived in Weimar to-day, and has
caused general excitement. In the course of the afternoon
I went to Goethe. ' Well ? ' he exclaimed as I entered,

90 THE HISTORY OF CREATION.

' what do you think of this great event ? The volcano has
burst forth, all is in flames, and there are no more negotia-
tions behind closed doors.' ' A dreadful affair,' I answered ;
' but what else could be expected under the circumstances,
and with such a ministry, except that it would end in the
expulsion of the present royal family ? ' ' We do not seem
to understand each other, my dear friend,' replied Goethe.
' I am not speaking of those people at all ; I am interested
in something very different. I mean the dispute between
Cuvier and Geoffroy de Saint Hilaire, which has broken
out in the Academy, and which is of such great importance
to science.' This remark of Goethe's came upon me so
unexpectedly, that I did not know what to say, and my
thoughts for some minutes seemed to have come to a com-
plete standstill. ' The affair is of the utmost importance,'
he continued, ' and you cannot form any idea of what I felt
on receiving the news of the meeting on the 19th. In
Geoffroy de Saint Hilaire we have now a mighty ally for a
long time to come. But I see also how great the sympathy
of the French scientific world must be in this affair, for, in
spite of the terrible political excitement, the meeting on
the 19th was attended by a full house. The best of it is,
however, that the synthetic treatment of nature, introduced
into France by Geoffroy, can now no longer be stopped.
This matter has now become public through the discussions
in the Academy, carried on in the presence of a large
audience ; it can no longer be referred to secret committees,
or be settled or suppressed behind closed doors.' "

In my book on " The General Morphology of Organisms "
I have placed as headings to the different books and chapters
a selection of the numerous interesting and important sen-

GOETHE ON ADAPTATION AND INHERITANCE. 9 1

tences in which Goethe clearly expresses his view of organic
nature and its constant development. I will here quote a
passage from the poem entitled, "The Metamorphosis of
Animals " (1819).

"AE members develop themselves according to eternal laws,
And the rarest form mysteriously preserves the primitive type.
Form therefore determines the animal's way of life,
And in turn the way of life powerfully reacts upon all form.
Thus the orderly growth of form is seen to hold
Whilst yielding to change from externally acting causes." *

Here, clearly enough, the contrast between two different
organic constructive forms is intimated, which are opposed
to one another, and which by their interaction determine
the form of the organism ; on the one hand, a common inner
original type, firmly maintaining itself, constitutes the
foundation of the most different forms ; on the other hand,
the externally active influence of surroundings and mode
of life, which influence the original type and transform it.
This contrast is still more definitely pointed out in the
following passage : —

" An inner original community forms the foundation of all
organization ; the variety of forms, on the other hand, arises
from the necessary relations to the outer world, and we
may therefore justly assume an original difference of con-
ditions, together with an uninterruptedly progressive trans-
formation, in order to be able to comprehend the constancy
as well as the variations of the phenomena of form."

* " Alle Glieder bilden sich aus nach ew'gen Gesetzen,

Und die seltenste Form bewahrt im Geheimniss das Urbild.
Also bestimmt die Gestalt die Lebensweise des Thieres.
Und die Weise zu leben, sie wirkt auf alle Gestalten
Machtig zuriick. So zeiget sich fest die geordnete Bildung,
Welche zum Wechsel sich neigt durch ausserlich wirkende Wesen."

92 THE HISTORY OF CREATION.

The " original type " which constitutes the foundation of
every organic form "as the inner original community" is
the inner constructive force, which receives the original
direction of form-production — that is, the tendency to give
rise to a particular form — and is propagated by Inheritance.
The " uninterruptedly progressive transformation," on the
other hand, which " springs from the necessary relations to
the outer world," acting as an external formative force,
produces, by Adaptation to the surrounding conditions of
life, the "infinite variety of forms." The internal formative
tendency of Inheritance, which retains the unity of the
original type, is called by Goethe in another passage the
centripetal force of the organism, or its tendency to specifica-
tion ; in contrast with this he calls the external formative
tendency of Adaptation, which produces the variety of
organic forms, the centrifugal force of organisms, or their
tendency to variation. The passage in which he clearly
indicates the " equilibrium " of these two extremely im-
portant organic formative tendencies, rune as follows : " The
idea of metamorphosis resembles the vis centrifuga, and
would lose itself in the infinite, if a counterpoise were not
added to it: I mean the tendency to specification, the
strong power to preserve what once has come into being,
a vis centripeta, which in its deepest foundation cannot be
affected by anything external."

Metamorphosis, according to Goethe, consists not merely,
as the word is now generally understood, in the changes of
form which the organic individual experiences during its
individual development, but, in a wider sense, in the ;
transformation of organic forms in general. His idea of!
metamorphosis is almost synonymous with the theory of

GOETHE'S SPECULATIONS. 93

development. This is clear, among other things, from the
following passage: "The triumph of physiological meta-
morphosis manifests itself where the whole separates and
transforms itself into families, the families into genera, the
genera into species, and then again into other varieties
down to the individual. This operation of Nature goes on
ad infinitum ; she cannot rest inactive, but neither can she
keep and preserve all that she has produced. From seeds
^here are always developed varying plants, exhibiting the
relations of their parts to one another in an altered manner."
Goethe had, in truth, discovered two great mechanical
forces of nature, which are the active causes of organic
formations, his two organic formative tendencies — on the
one hand the conservative, centripetal, and internal forma-
tive tendency of Inheritance or specification; and on the
other hand the progressive, centrifugal, and external forma-
tive tendency of Adaptation, or metamorphosis. This pro-
found biological intuition could not but lead him naturally
to the fundamental idea of the Doctrine of Filiation, that
is, to the conception that the organic species resembling one
another in form are actually related by blood, and that they
are descended from a common original type. In regard to .
the most important of all animal groups, namely that of
Vertebrate animals, Goethe (in 1796 !) expresses this
doctrine in the following passage : " Thus much, then, we
have gained, that we may assert without hesitation that all
the more perfect organic natures, such as fishes, amphibious
animals, birds, mammals, and man at the head of the last,
were all formed upon one original type, which varies only
more or less in parts which are none the less permanent, and
still daily changes and modifies its form by propagation."

94 THE HISTORY OF CREATION.

This sentence is of interest in more than one way. The
theory that all " the more perfect organic natures," that is
all Vertebrate animals, are descended from one common
prototype, that they have arisen from it by propagation
(Inheritance) and transformation (Adaptation), may be dis-
tinctly inferred. But it is especially interesting to observe
that Goethe admits no exceptional position for man, but
rather expressly includes him in the tribe of the other
Vertebrate animals. The most important special inference
of the Doctrine of Filiation, that man is descended from
other Vertebrate animals, may here be recognized in the
germ. 3

This exceedingly important fundamental idea is expressed
by Goethe still more clearly in another passage (1807), in
the following words : " If we consider plants and animals
in their most imperfect condition, they can scarcely be dis-
tinguished. But this much we can say, that the creatures
which by degrees emerge as plants and animals out of a
common phase, where they are barely distinguishable, arrive
at perfection in two opposite directions ; so that the plant
in the end reaches its highest glory in the tree, which is
immovable and stiff, the animal in man, who possesses the
greatest mobility and freedom." This remarkable passage
not only indicates most explicitly the genealogical relation-
ship between the vegetable and animal kingdoms, but con-
tains the germ of the monistic or monophyletic hypothesis
of descent, the importance of which I shall have to explain
hereafter.

— At the time when Goethe in this way sketched the
fundamental features of the Theory of Descent, another
German philosopher, Gottfried Reinhold Treviranus, of

TKEVIEANUS, THE FIEST NATTJBE-PHILOSOPHER. 95

Bremen (born 1776, died 1837), was zealously engaged at
the same work. As Wilhelm Focke has recently shown,
Treviranus, even in the earliest of his greater works, " The
Biology or Philosophy of Animate Nature," which appeared
at the beginning of the present century, had already
developed monistic views of the unity of nature, and of the
genealogical connection of the species of organisms, which
entirely correspond with our present view of the matter.
In the first three volumes of his Biology, which appeared
successively in 1802, 1803, and 1805 (therefore several years
before Oken's and Lamarck's principal works), we find
numerous passages which are of interest in this respect. I
shall here quote only a few of the most important.

In speaking of the principal question of our theory, the
question of the origin of organic species, Treviranus makes
the following remarks : " Every form of life can be pro-
duced by physical forces in one of two ways : either by
coming into being out of formless matter, or by the modifi-
cation of an already existing form by a continued process
of shaping. In the latter case the cause of this modification
may lie either in the influence of a dissimilar male genera-
tive matter upon the female germ, or in the influence of
other powers which operate only after procreation. In
every living being there exists the capability of an endless
variety of form- assumption ; each possesses the power to
adapt its organization to the changes of the outer world,
and it is this power put into action by the change of the
universe that has raised the simple zoophytes of the
primitive world to continually higher stages of organization,
and has introduced a countless variety of species into
animate nature."

g6 THE HISTOEY OF CREATION.

By zoophytes, Treviranus here means organisms of the
lowest order and of the simplest character, namely, those
neutral primitive beings which stand midway between
animals and plants, and on the whole correspond with our
protista. " These zoophytes," he remarks in another pas-
sage, " are the original forms out of which all the organisms
of the higher classes have arisen by gradual development.
We are further of opinion that every species, as well as
every individual, has certain periods of growth, of bloom,
and of decay, but that the decay of a species is degeneration,
not dissolution, as in the case of the individual. From this it
appears to us to follow that it was not the great catastrophes
of the earth (as is generally supposed) which destroyed the
animals of the primitive world, but that many survived
them, and it is more probable that they have disappeared
from existing nature, because the species to which they
belonged have completed the circle of their existence, and
have become changed into other kinds."

When Treviranus, in this and other passages, points to
degeneration as the most important cause of the transforma-
tion of the animal and vegetable species, he does not under-
stand by it what is now commonly called degeneration.
With him " degeneration " is exactly what we now call
Adaptation or modification, by the action of external
formative forces. That Treviranus explained this trans-
formation of organic species by Adaptation, and its preserva-
tion by Inheritance, and thus the whole variety of organic
forms by the interaction of Adaptation and Inheritance, is
clear also from several other passages. How profoundly he
grasped the mutual dependence of all living creatures on
one another, and in general the universal connection

TKEVIRANTJS ON SOLIDARITY. 97

between cause and effect — that is, the monistic causal con-
nection between all members and parts of the universe — is
further shown, among others, by the following remarks in
his Biology : " The living individual is dependent upon
the species, the species upon the fauna, the fauna upon the
whole of animate nature, and the latter upon the organism
of the earth. The individual possesses indeed a peculiar
life, and so far forms its own world. But just because its
life is limited it constitutes at the same time an organ in
the general organism. Every living body exists in con-
sequence of the universe, but the universe, on the other
hand, exists in consequence of it."

It is self-evident that so profound and dear a thinker as
Treviranus, in accordance with this grand mechanical con-
ception of the universe, could not admit for man a privileged
and exceptional position in nature, but assumed his gradual
development from lower animal forms. And it is equally
self-evident, on the other hand, that he did not admit a
chasm between organic and inorganic nature, but main-
tained the absolute unity of the organization of the whole
universe. This is specially attested by the following
sentence : " Every inquiry into the influence of the whole
of nature on the living world must start from the principle
that all living forms are products of physical influences,
which are acting even now, and are changed only in degree,
or in their direction." Hereby, as Treviranus himself says,
"the fundamental problem of biology is solved," and we
add, solved in a purely mechanical or monistic sense.

Yet neither Treviranus nor Goethe is commonly con-
sidered the most eminent of the German nature-philosophers.
This honour was reserved for Lorenz Oken, who, in estab-

VOL. I. H

98 THE HISTORY OF CREATION.

lishing the vertebral theory of the skull, came forward as a
rival to Goethe, and did not entertain a very kindly feeling
towards him. Although they lived for some time in the
same neighbourhood, yet the natures of these two men were
so very different, that they could not well be drawn towards
each other. Oken's " Manual of the Philosophy of Nature,"
which may be designated as the most important production
of the nature-philosophy school then existing in Germany,
appeared in 1809, the same year in which Lamarck's funda-
mental work, the " Philosophie Zoologique," was published.
As early as 1802, Oken had published an " Outline of the
Philosophy of Nature." As we have already intimated, in
Oken's as in Goethe's works, a number of valuable and
profound thoughts are hidden among a mass of erroneous,
very eccentric, and fantastic conceptions. Some of these
ideas have only quite recently and gradually become recog-
nized in science, many years after they were first expressed.
I shall here quote only two thoughts, which are almost
prophetic, and which at the same time stand in the closest
relation to the theory of development.

One of the most important of Oken's theories, which was
formerly very much decried, and was most strongly com-
batted, especially by the so-called " exact experimentalists,"
is the idea that the phenomena of life in all organisms pro-
ceed from a common chemical substance, so to say, from a
general simple vital-substance, which he designated by the
name Urschleim, that is, original slime. By it he meant, as
the name indicates, a mucilaginous substance, an albuminous
combination, which exists in a semi-fluid condition of aggre-
gation, and possesses the power, by adaptation to different
conditions of existence in the outer world and by inter-

OKEN'S THEORIES. 99

action with its material, of producing the most various forms.
Now, we need only change the expression " original slime "
(Urschleim) into Protoplasm, or cell-substance, in order to
arrive at one of the grandest results which we owe to
microscopic investigations during the last twenty years,
more especially to those of Max Schultze. By these investi-
gations it has been shown that in all living bodies, without
exception, there exists a certain quantity of mucilaginous
albuminous matter, in a semi-fluid condition ; and that this
nitrogen-holding carbon-compound is exclusively the ori-
ginal seat and agent of all the phenomena of life, and of all
production of organic forms. All other substances which
appear in the organism are either formed by this active
matter of life, or have been introduced from without. The
organic egg, the original cell out of which every animal and
plant is first developed, consists essentially only of one
round little lump of such albuminous matter. Even the
yolk of an egg is nothing but albumen, mixed with granules
of fat. Oken was therefore right when, more divining than
knowing, he made the assertion— " Every organic thing has
arisen out of slime, and is nothing but slime in different
forms. This primitive slime originated in the sea, from
inorganic matter in the course of planetary evolution."

Another equally grand idea of the same philosopher is
closely connected with his theory of primitive slime, which
coincides with the extremely important Protoplasm theory.
For Oken, as early as 1809, asserted that the primitive
slime produced in the sea by spontaneous generation, at
once assumed the form of microscopically small bladders,
which he called " Mile," or "Infusoria." " Organic nature
has for its basis an infinity of such vesicles." These little

IOO THE HISTOEY OF CREATION.

bladders arise from original semi-fluid globules of the primi-
tive slime, by the fact of their periphery becoming con-
densed. The simplest organism, as well as every animal
and every plant of higher kind, is nothing else than " an
accumulation (synthesis) of such infusorial bladders, which
by various combinations assume various forms, and thus
develop into higher organisms." Here again we need only
translate the expression little bladder, or infusorium, by
the word cell, and we arrive at the Cell theory, one of the
grandest biological theories of our century. Schleiden and
Schwann, in 1838, were the first to furnish experiential
proof that all organisms are either simple cells, or accumu-
lations (syntheses) of such cells, and the more recent proto-
plasm theory has shown that protoplasm (the original slime)
is the most essential (and sometimes the only) constituent
part of the genuine cell. The properties which Oken
ascribes to his Infusoria are exactly the properties of cells,
the properties of elementary beings, by whose accumulation,
combination, and varying development the higher organisms
are formed.

These two extremely fruitful thoughts of Oken, on account
of the absurd form in which he expressed them, were at
first little heeded, or entirely misunderstood, and it was
reserved for a much later era to establish them by actual
observation. Other principles of the theory of descent also
stood in the closest connection with Oken's ideas. Of the
origin of the human race Oken asserts, " Man has been
developed, not created." Although many arbitrary per-
versities and extravagant fancies may be found in Oken's
philosophy of nature, they must not prevent us paying our
just admiration to his grand ideas, which were so far in

THE NATUR-PHILOSOPHIE. IOI

advance of their age. This much is clearly evident from
the statements of Goethe and Oken which we have quoted,
and from the views of Lamarck and GeofFroy which have
to be discussed next, that during the first decade of our
century no doctrine approached so nearly to the natural
Theory of Descent, newly established by Darwin, as Oken's
much-decried " Natur-philosophie."

102 THE HISTORY OF CREATION.

CHAPTER V.

THEORY OF DEVELOPMENT ACCORDING TO KANT
AND LAMARCK.

Kant's Services to the Theory of Development. — His Monistic Cosmology
and Dualistic Biology. — Contradiction between the Mechanical and
Teleological Conception. — Comparison of Genealogical Biology with
Comparative Philology. — Views in favonr of the Theory of Descent
entertained by Leopold Buch, Bar, Schleiden, Unger, Schaaffhausen,
Victor Cams, Biichner. — French Nature-Philosophy. — Lamarck's Philo-
sophic Zoologique. — Lamarck's Monistic (mechanical) System of
Nature. — His Views of the Interaction of the Two Organic Formative
Tendencies of Inheritance and Adaptation. — Lamarck's Conception of
Man's Development from Ape-like Mammals. — Geoffrey St. Hilaire's,
Naudin's, and Lecoq's Defence of the Theory of Descent. — English
Nature-Philosophy. — Views in favour of the Theory of Descent, enter-
tained by Erasmus Darwin, W. Herbert, Grant, Freke, Herbert
Spencer, Hooker, Huxley. — The Double Merit of Charles Darwin.

The teleological view of nature, which explains the phe-
nomena of the organic world by the action of a personal
Creator acting for a definite purpose, necessarily leads, when
carried to its extreme consequences, either to utterly unten-
able contradictions, or to a twofold (dualistic) conception
of nature, which most directly contradicts the unity and
simplicity of the supreme laws which are everywhere
perceptible. The philosophers who embrace teleology must
necessarily assume two fundamentally different natures :

KANT'S BIOLOGICAL THEORIES. 103

an inorganic nature, which must be explained by causes
acting mechanically (causae efficientes), and an organic
nature, -which must be explained by causes acting for a
definite purpose (causae finales). (Compare p. 35.)

This dualism meets us in a striking manner when con-
sidering the conceptions of nature formed by Kant, one
of the greatest German philosophers, and his ideas of the
coming into being of organisms. A closer examination of
these ideas is forced upon us here, because in Immanuel Kant
we honour one of the few philosophers who combine a solid
scientific culture with an extraordinary clearness and pro-
fundity of speculation. The Konigsberg philosopher gained
the highest celebrity, not only among speculative philo-
sophers as the founder of critical philosophy, but acquired
a brilliant name also among naturalists by his mechanical
cosmogony. As early as the year 1755, in his "General
History of Nature, and Theory of the Heavens," 22 he made
the bold attempt " to discuss the constitution and the
mechanical origin of the whole universe, according to
Newton's principles," and to explain them mechanically by
the natural course of development, to the exclusion of all
miracles. This cosmogony of Kant, or " cosmological gas
theory," which we shall briefly discuss in a future chapter,
was at a later day fully established by the French mathe-
matician Laplace and the English astronomer Herschel, and
enjoys at the present day almost universal recognition. On
account of this important work alone, in which exact know-
ledge is coupled with most profound speculation, Kant
deserves the honourable name of a natural philosopher in
the best and purest sense of the word.

Now, in various works of Immanuel Kant, especially in

104 THE HISTOBY OF CREATION.

those written in his earlier years (between 1755 and 1775),
are scattered a number of very important passages which
would justify our placing him, by the side of Lamarck and
Goethe, as the principal and most eminent of Darwin's
precursors. Professor Fritz Schultze, of Dresden, has done
important work by collecting and giving a critical explana-
tion of these very interesting but little known passages
from the writings of the great Kbnigsberg philosopher.
Schultze's work is entitled, " Kant und Darwin," a contri-
bution to the history of the Theory of Development (Jena,
1 875). From the passages quoted by Schultze, it is quite
evident that Kant had, at that time, clearly and perfectly
grasped the great idea of the unity of nature (pp. 32, 46),
and the monistic conception of development that embraces
all nature. Hence he not only maintains the derivation of
the various organisms from common primary forms (the
theory of descent !), the degeneration from the primary
form of the species by natural wanderings (the migration
theory ! p. 65), but he likewise assumes (as early as
1771 !) " that the original mode of walking in man was to
proceed on four feet, that to walk upright on two feet
was undertaken only by degrees, and that man has only
gradually, proudly raised his head above his old comrades,
the animals " (I.e., 47-50). Kant, moreover, was the first
to discover the principle of the " Struggle for Existence "
and the theory of Selection, as we shall presently see (I.e.,
25, 56, 57, 61, 140, etc.).

For these reasons we should unconditionally have to
assign the place of honour in the history of the Theory
of Development to our mighty Kbnigsberg philosopher,
were it not that, unfortunately, these remarkable monistic

KANT'S FAILURE. 1 05

ideas of young Kant were at a subsequent period wholly
suppressed by the overwhelming influence of the dualistic,
Christian conception of the universe. In Kant's later
works, in place of his earlier ideas, we have either utterly
untenable dualistic conceptions, or an indefinite wavering
between the former and the latter ideas.

When we read Kant's Criticism of the Teleological
Faculty of Judgment, his most important biological work,
we perceive that in contemplating organic nature he always
maintains what is essentially the teleological or dualistic
point of view ; whilst for inorganic nature he, uncondition-
ally and without reserve, assumes the mechanical or monis-
tic method of explanation. He affirms that in the domain
of inorganic nature all the phenomena can be explained by
mechanical causes, by the moving forces of matter itself, but
not so in the domain of organic nature. In the whole of
Anorganology (in Geology and Mineralogy, in Meteorology
and Astronomy, in the physics and chemistry of inorganic
natural bodies), all phenomena are said to be explicable
merely by mechanism, (causa efficiens), without the interven-
tion of a final purpose. In the whole domain of Biology, on
the other hand — in Botany, Zoology, and Anthropology —
mechanism is not considered sufficient to explain to us all
their phenomena ; we are supposed to be able to comprehend
them only by an assumption of a final cause acting for a
definite purpose (causa finalis). In several passages Kant
emphatically remarks that, from a strictly scientific point of
view, all phenomena, without exception, require a mechani-
cal interpretation, and that mechanism alone can offer a true
explanation. But at the same time be thinks, that in regard
to living natural bodies, animals and plants, our human

106 THE HISTOEY OF CEEATION.

power of comprehension is limited, and not sufficient for
arriving at the real cause of organic processes, especially at
the origin of organic forms. The right of human reason to
explain all phenomena mechanically is unlimited, he says,
but its power is limited by the fact that organic nature
can be conceived only from a teleological point of
view.

In other passages again Kant quits this dualistic point
of view, and even asserts the necessity of a genealogical
conception of the series of organisms, if we at all wish to
understand it scientifically. The most important and
remarkable of these passages occurs in his " Methodical
System of the Teleological Faculty of Judgment " (§ 79),
which appeared in 1790 in the " Criticism of the Faculty of
Judgment." Considering the extraordinary interest which
this passage possesses, both for forming a correct estimate
of Kant's philosophy, as well as for the Theory of Descent,
I shall here insert it verbatim.

" It is desirable to examine the great domain of organized
beings by means of a methodical comparative anatomy, in
order to discover whether we may not find in them some-
thing resembling a system, and that too in connection with
their mode of generation, so that we may not be compelled
to stop short with a mere consideration of forms as they
are — -which gives us no insight into their generation —
and need not despair of gaining a full insight into this de-
partment of nature. The agreement of so many kinds of
animals in a certain common plan of structure, which seems
to be visible not only in their skeletons, but also in the
arrangement of the other parts — so that a wonderfully
simple typical form, by the shortening and lengthening

KANT'S DOCTRINE OF DESCENT. 107

of some parts, and by the suppression and development of
others, might be able to produce an immense variety of
species — gives us a ray of hope, though feeble, that here
perhaps some result may be obtained, by the application of
the principle of the mechanism of nature, without which,
in fact, no science can exist. This analogy of forms (in so
far as they seem to have been produced in accordance with
a common prototype, notwithstanding their great variety)
strengthens the supposition that they have an actual blood-
relationship, due to derivation from a common parent ;
a supposition ' which is arrived at by observation of the
graduated approximation of one class of animals to another,
beginning with the one in which the principle of purposive-
ness seems to be most conspicuous, namely man, and extend-
ing down to the polyps, and from these even down to mosses
land lichens, and arriving finally at raw matter, the lowest
stage of nature observable by us. From this raw matter
land its forces, the whole apparatus of Nature seems to have
been derived according to mechanical laws (such as those
Which resulted in the production of crystals) ; yet this
'apparatus, as seen in organic beings, is so incomprehensible
to us, that we feel ourselves compelled to conceive for it a
different principle. But it would seem that the archaeologist
of Nature is at liberty to regard the great Family of
creatures (for as a Family we must conceive it, if the above-
mentioned continuous and connected relationship has a real
foundation) as having sprung from the immediate results of
her earliest revolutions, judging from all the laws of their
mechanism known to or conjectured by him."

If we take this remarkable passage and consider it by
itself, we cannot but be astonished to find how profoundly

108 THE HISTORY OF CREATION.

and clearly the great thinker had recognized the inevitable
necessity of the Doctrine of Descent, and designated it as
the only possible way of explaining organic nature by
mechanical laws — that is, by true scientific reasoning. But
as soon as we consider this passage in connection with the
other train of thoughts in the " Criticism of the Faculty
of Judgment," and balance it against other directly con-
tradictory passages, we see clearly that Kant, in these and
some similar (but weaker) sentences, went beyond himself,
and abandoned the teleological point of view which he
usually adopts in Biology.

Even directly after the passage just quoted, there follows
a remark which completely takes off its edge. After having
quite correctly maintained the origin of organic forms out
of raw matter by mechanical laws (in the manner of
crystallization), as well as a gradual development of the
different species by descent from one common original;
parent, Kant adds, " But he (the archaeologist of nature,!
that is the palaeontologist) must for this end ascribe to the;
common mother an organization ordained purposely with
a view to the needs of all her offspring, otherwise the
possibility of suitability of form in the products of the
animal and vegetable kingdoms cannot be conceived at all."
This addition clearly contradicts the most important funda-
mental thought of the preceding passage, viz. that a purely
mechanical explanation of organic nature becomes possible
through the Theory of Descent. And that the teleological
conception of organic nature predominated with Kant, is
shown by the heading of the remarkable § 79, which con-
tains the two contradictory passages cited: " Of the Necessary
Subordination of the Mechanical to the Teleological Prin-

AN IMPOSSIBLE NEWTON. 109

ciple, in the explanation of a thing as a purpose or object
of Nature''

He expresses himself most decidedlyagainstthe mechanical
explanation of organic nature in the following passage
(§ 74) : " It is quite certain that we cannot become sufficiently
acquainted with organized creatures and their hidden
potentialities by aid of purely mechanical natural principles,
much less can we explain them ; and this is so certain, that
we may boldly assert that it is absurd for man even to con-
ceive such an idea, or to hope that a Newton may one day
arise able to make the production of a blade of grass com-
prehensible, according to natural laws ordained by no inten-
tion ; such an insight we must absolutely deny to man."
However, this impossible Newton did really appear seventy
years later in Darwin, whose Theory of Selection has
actually solved the problem, the solution of which Kant
had considered absolutely inconceivable.

In connection with Kant and the German philosophers
whose theories of development have already occupied us in
the preceding chapter, it seems justifiable to consider briefly
some other German naturalists and philosophers, who, in the
course of our century, have more or less distinctly resisted
the prevailing teleological views of creation, and vindicated
the mechanical conception of things which is the basis of
the Doctrine of Filiation. Sometimes, general philosophical
considerations, sometimes special empirical observations,
were the motives which led these thinking men to form the
idea that the various individual species of organisms must
have originated from common primary forms. Among them
I must first mention the great German geologist, Leopold
Buch. Important observations as to the geographical dis-

IIO THE HISTOEY OF CREATION.

tribution of plants led him to the following remarkable
assertion in his excellent " Physical Description of the
Canary Islands " : —

" The individuals of genera, on continents, spread and
widely diffuse themselves, and owing to the difference of
localities, nourishment, and soil, form varieties; and in
consequence of their isolation never being crossed by other
varieties, and so brought back to the main type, they
in the end become a permanent and a distinct species.
Then, perhaps, in other ways, they meet with other de-
scendants of the original form — which have likewise be-
come new varieties — and both now appear as very distinct
species, no longer mingling with one another. Not so on
islands. Being commonly confined in narrow valleys or
within the limit of small zones, individuals can reach one
another and destroy every commencing production of a per-
manent variety. Much in the same way the peculiarities or
faults in language, originating with the head of some family,
become, through the extension of the family, indigenous
throughout a whole district. If the district is separated
and isolated, and if the language is not brought back to its
former purity by constant connection with that spoken in
neighbouring districts, a dialect will be the result. If
natural obstacles, forests, constitution, form of government,
unite the inhabitants of the separate district still more
closely, and separate them still more completely from their
neighbours, the dialect is fixed, and becomes a completely
distinct language" ("TTebersicht der Flora auf den Canarien,"
S. 133).

We perceive that Buch is here led to the fundamental
idea of the Theory of Descent by the phenomena of the

LEOPOLD BUCH. Ill

geography of plants, a department of biological knowledge
which in fact furnishes a mass of proofs in favour of it.
Darwin has minutely discussed these proofs in two separate
chapters of his book (the 11th and 12th). Buch's remark is
further of interest, because it leads us to the exceedingly
instructive comparison of the different branches of language
with the species of organisms, a comparison which is of the
greatest use to Comparative Philology, as well as to Compara-
tive Botany and Zoology. Just as, for example, the different
dialects, provincialisms, branches, and off-shoots of the
German, Slavonic, Greco-Latin, and Irano-Indian parent
language are derived from a single common Indo-Germanic
parent tongue, and just as their differences are explained by
Adaptation, and their common fundamental characters ex-
plained by Inheritance, so in like manner the different species,
genera, families, orders, and classes of Vertebrate animals
are derived from a single common vertebrate form of animal.
Here also Adaptation is the cause of differences, Inheritance
the cause of community of character. This interesting
parallelism in the divergent development of the forms of
speech and the forms of organisms has been discussed in
the clearest manner by one of our first comparative philolo-
gists, the talented Augustus Schleicher ; his work consisted,
more especially, in tracing phylogenetically the pedigree
of the Indo-Germanic languages, and this he did with much
ingenuity. 6

Among other eminent German naturalists who have ex-
pressed their belief in the Theory of Descent more or less
distinctly, arriving at their conclusion in very various wa3 7 s,
I must next mention Carl Ernst Bar, the great reformer of
animal embryology. In a lecture delivered in 1834, entitled

112 THE HISTORY OF CREATION.

" The Most General Laws of Nature in All Development,"
he shows, in the clearest way, that only in a very childish
view of nature could organic species be regarded as perma-
nent and unchangeable types, and that in fact they can be
only passing series of generations, which have developed by
transformation from a common original form. The same
conception again received firm support from Baer, in 1859,
through a consideration of the laws of the geographical
distribution of organisms.

J. M. Schleiden, who founded, fifty years ago, in Jena, a
new epoch in Botany by his strictly empirico-philosophical
and truly scientific method, illustrated the philosophical
significance of the conception of organic species in his inci-
sive " Outlines of Scientific Botany," 7 and showed that it
had only a subjective origin in the general law of specifica-
tion. The different species of plants are only the specified
productions of the formative tendencies of plants, which
arise from the various combinations of the fundamental
forces of organic matter.

The eminent botanist, F. Unger, of Vienna, was led by
his profound and comprehensive investigations on extinct
vegetable species, to a palseontological history of the de-
velopment of the vegetable kingdom, which distinctly asserts
the principle of the Theory of Descent. In his "Attempt
at a History of the World of Plants " (1852), he maintains
the derivation of all different species of plants from a few
primary forms, and perhaps from a single original plant, a
simple vegetable cell. He shows that this view is founded
on the genetic connection of all vegetable forms, and is
necessary, not merely for philosophical reasons, but for
those of experience and observation. 8

CAR US, SCHAAFFHAUSEN, BUCHNER. 113

Victor Carus, of Leipzig, in the Introduction to his
excellent " System of Animal Morphology," 9 published in
1853, makes the following remark : " The organisms buried
in the most ancient geological strata must be looked upon
as the ancestors from whom the rich diversity of forms of
the present creation have originated by continued genera-
tion, and by accommodation to progressive and very different
conditions of life."

In the same year (1853) Schaaffhausen, the anthropologist
of Bonn, in an Essay " On the Permanence and Transforma-
tion of Species," declared himself decidedly in favour of the
Theory of Descent. According to him, the living species of
animals and plants are the transformed descendants of ex-
tinct species, from which they have arisen by gradual modi-
fication. The divergence or separation of the most nearly
allied species takes place by the destruction of the connect-
ing intermediate stages. Schaaffhausen also maintained
the origin of the human race from animals, and its gradual
development from ape-like animals, the most important
deduction from the Doctrine of Filiation.

Lastly, we have still to mention among the German Nature-
philosophers the name of Louis Biichner, who, in his cele-
brated work, " Force and Matter " (1855), also independently
developed the principles of the Theory of Descent, taking
his stand mainly on the ground of the undeniable evidences
of facts which are furnished by the palseontological and in-
dividual development of organisms, as well as by their com-
parative anatomy and by the parallelism of these series of
development. Biichner showed very clearly that, even from
such data alone, the derivation of the different organic
species from common primary forms followed as a necessary

VOL. I. I

114 THE HISTORY OF CREATION.

conclusion, and that the origin of these original primary
forms could only be conceived of as the result of a spon-
taneous generation.

We now turn from the German to the French Nature-
philosophers, who have likewise held the Theory of Descent,
since the beginning of the present century. At their head
stands Jean Lamarck, who occupies the first place next
to Darwin and Goethe in the history of the Doctrine of
Filiation. To him will always belong the immortal glory of
having for the first time worked out the Theory of Descent,
as an independent scientific theory of the first order, and as
the philosophical foundation of the whole science of Biology.
Although Lamarck was born as early as 1744, he did not
begin the publication of his theory until the commence-
ment of the present century, in 1801, and established it more
fully only in 1809, in his classic " Philosophic Zoologique." 2
This admirable work is the first connected exposition of
the Theory of Descent carried out strictly into all its con-
sequences. By its purely mechanical method of viewing
organic nature, and the strictly philosophical proofs brought
forward in it, Lamarck's work is raised far above the pre-
vailing dualistic views of his time ; and with the exception
of Darwin's work, which appeared just half a century later,
there is none which we could in this respect place by the
side of the "Philosophie Zoologique." How far it was
in advance of its time is perhaps best seen from the cir-
cumstance that it was not understood by most men, and for
fifty years was not spoken of at all. Cuvier, Lamarck's
greatest opponent, in his " Report on the Progress of Natural
Sciences," in which the most unimportant anatomical inves-
tigations are enumerated, does not devote a single word to

LAMARCK'S PHILOSOPHY. 1 1 5

this work, which forms an epoch in science. Goethe, also, who
took such a lively interest in the French nature-philosophy
and in "the thoughts of kindred minds beyond the Rhine,"
nowhere mentions Lamarck, and does not seem to have
known the "Philosophie Zoologique " at all. The great
reputation which Lamarck gained as a naturalist he does
not owe to his highly important general work, but to
numerous special treatises on the lower animals, particularly
on Molluscs, as well as to an excellent " Natural History of
Invertebrate Animals," which appeared, in seven volumes,
between the years 1815-1822. The first volume of this
celebrated work contains in the general introduction a
detailed exposition of his theory of filiation. I can, per-
haps, give no better idea of the extraordinary importance
of the " Philosophie Zoologique " than by quoting verbatim
some of the most important passages therefrom : —

"The systematic divisions of classes, orders, families,
genera, and species, as well as their designations, are the
arbitrary and artificial productions of man. The kinds or
species of organisms are of unequal age, developed one after
the other, and show only a relative and temporary persist-
ence ; species arise out of varieties. The differences in the
conditions of life have a modifying influence on the organi-
zation, the general form, and the parts of animals, and so
has the use or disuse of organs. In the first beginning only
the very simplest and lowest animals and plants came into
existence ; those of a more complex organization only at a
later period. The course of the earth's development, and
that of its organic inhabitants, was continuous, not inter-
rupted by violent revolutions. Life is purely a physical
phenomenon. All the phenomena of life depend on

Il6 THE HISTORY OF CREATION.

mechanical, physical, and chemical causes, which are in-
herent in the nature of matter itself. The simplest animals
and the simplest plants, which stand at the lowest point in
the scale of organization, have originated and still originate
by spontaneous generation. All animate natural bodies or
organisms are subject to the same laws as inanimate natural
bodies or anorgana. The ideas and actions of the under-
standing are the motional phenomena of the central nervous
system. The will is in truth never free. Reason is only a
higher degree of development and combination of judg-
ments."

These are indeed astonishingly bold, grand, and far-reach-
ing views, and were expressed by Lamarck eighty years ago,
in fact, at a time when their establishment, by a mass of
facts, was not nearly as possible as it is in our day. Indeed
Lamarck's work is really a complete and strictly monistic
(mechanical) system of nature, and all the important general
principles of monistic Biology are already enunciated by
him : the unity of the active causes in organic and inorganic
nature ; the ultimate explanation of these causes in the
chemical and physical properties of matter itself; the
absence of a special vital power, or of an organic final cause,
the derivation of all organisms from some few, most simple
original forms, which have come into existence by spon-
taneous generation out of inorganic matter; the coherent
course of the whole earth's history; the absence of
violent cataclysmic revolutions ; and in general the incon-
ceivableness of any miracle, of any supernatural interference,
in the natural course of the development of matter.

The fact that Lamarck's wonderful intellectual feat met
with scarcely any recognition, arises partly from the gigantic

LAMARCK ON ADAPTATION. 1 17

stride with which he had advanced beyond the next fifty

years, partly from its defective empirical foundation, and

from the somewhat one-sided character of some of his

arguments. Lamarck quite correctly recognizes Adaptation

as the first mechanical cause which effects the continual

transformation of organic forms, while he traces with equal

justice the similarity in form of different species, genera,

families, etc., to their blood-relationship, and thus explains

it by Inheritance. Adaptation, according to him, consists

in this, that the perpetual, slow change of the outer world

causes a corresponding change in the actions of organisms,

and thereby also causes a further change in their forms.

He lays the greatest stress upon the effect of habit upon

the use and disuse of organs. This is certainly of great

importance in the transformation of organic forms, as we

shall see later. However, the way in which Lamarck

wished to explain exclusively, or at any rate mainly, the

change of forms, is after all in most cases not possible.

He says, for example, that the long neck of the giraffe has

arisen from its constantly stretching out its neck at high

trees, and from the endeavour to pick the leaves off their

branches ; that as giraffes generally inhabit dry districts,

where only the foliage of trees afford them nourishment,

they were forced to this action. In like manner the long

tongues of woodpeckers, humming-birds, and ant-eaters are

said by him to have arisen from the habit of fetching their

food out of narrow, small, and deep crevices or channels.

The webs between the toes of the webbed feet in frogs and

other aquatic animals, he says, have arisen solely from the

constant endeavour to swim, from striking their feet against

the water, and from the very movements of swimming.

Il8 THE HISTOKY OF CKEATION.

Inheritance, he says, fixed these habits on the descendants,
and finally, by further elaboration, the organs were entirely
transformed. However correct, as a whole, this fundamental
thought may be, yet Lamarck lays the stress too exclusively
on habit (use and non-use of organs), certainly one of the
most important, but not the only cause of the change of
forms. Still this cannot prevent our acknowledging that
Lamarck quite correctly appreciated the mutual co-operation
of the two organic formative tendencies of Adaptation and
Inheritance. What he failed to grasp is the exceedingly
important principle of " Natural Selection in the Struggle
for Existence," with which Darwin, fifty years later, made
us acquainted.

It still remains to be mentioned as a special merit of
Lamarck, that he endeavoured to prove the development of
the human race from other primitive, ape-like mammals.
Here again it was, above all, to habit that he ascribed the
transforming, the ennobling influence. He assumed that the
lowest, original men had originated out of men-like apes, by
the latter accustoming themselves to walk upright. The
raising of the body, the constant effort to keep upright, in
the first place led to a transformation of the limbs, to a
stronger differentiation or separation of the fore and hinder
extremities, which is justly considered one of the most
essential distinctions between man and the ape. Behind,
the calf of the leg and the flat soles of the feet were
developed ; in front, the arms and hands, for the purpose of
seizing objects. The upright walk was then followed by a
freer view over the surrounding objects, and led consequently
to an important progress in mental development. Human
apes thereby soon gained a great advantage over the other

GEOFFEOY ST. HILAIEB. 1 19

apes, and further, over surrounding, organisms in general.
In order to maintain the supremacy over them, they
formed themselves into companies, and there arose, as in the
case of all animals living in company, the desire of com-
municating to one another their desires and thoughts. Thus
arose the necessity of language, which, consisting at first of
rough and disjointed sounds, soon became more connected,
developed, and articulate. The development of articulate
speech now in turn became the strongest lever for a further
progressive development of the organism, and, above all, of
the brain, and so ape-like men became gradually and slowly
transformed into real men. In this way the actual descent
of the lowest and rudest primitive men from the most highly
developed apes was distinctly maintained by Lamarck, and
supported by a series of the most important proofs.

The honour of being the chief French nature-philosopher
is not usually assigned to Lamarck, but to Etienne Geoffroy
St. Hilaire (the elder), born in 1771, the same in whom
Goethe was especially interested, and with whom we have
already become acquainted as Cuvier's most prominent
opponent. He developed his ideas about the transformation
of organic species as far back as the end of the last century,
but published them only in the year 1828, and then in the
following years, especially in 1830, defended them bravely
against Cuvier. Geoffroy St. Hilaire in all essentials
adopted Lamarck's Theory of Descent, yet he believed that
the transformation of animal and vegetable species was less
effected by the action of the organism itself (by habit,
practice, use or disuse of organs) than by the "monde
ambiant," that is, by the continual change of the outer
world, especially of the atmosphere. He conceives the

T20 THE HISTORY OF CREATION.

organism as passive, in regard to the vital conditions of
the outer world, while Lamarck, on the contrary, regards it
as active. Geoffroy thinks, for example, that birds origi-
nated from lizard-like reptiles, simply by a diminution of
the carbonic acid in the atmosphere, in consequence of which
the breathing process became more animated and energetic
through the increased proportion of oxygen in the atmo-
sphere. Thus there arose a higher temperature of the blood,
an increased activity of the nerves and muscles, and the
scales of the reptiles became the feathers of the birds, etc.
This conception is based upon a correct thought, but although
the change of the atmosphere, as well as the change of every
other external condition of existence, certainly effects
directly or indirectly the transformation of the organism,
yet this single cause is by itself too unimportant for such
effects to be ascribed to it. It is even less important than
practice and habit, upon which Lamarck lays too much
stress. Geoffrey's chief merit consists in his having vindi-
cated the monistic conception of nature, the unity of
organic forms, and the deep genealogical connection of the
different organic types in the face of Ouvier's powerful
influence. I have already mentioned in the preceding
chapter the celebrated disputes between the two great
opponents in the Academy of Paris, especially the fierce
conflicts on the 22nd of February and on the 19th of
July, in which Goethe took so lively an interest. On that
occasion Cuvier remained the acknowledged victor, and
since that time very little, or rather nothing, more has been
done in France to further the development of the Doctrine
of Filiation, and to complete the monistic theory of develop-
ment. This is evidently to be ascribed principally to the

EKASMUS DAKWIST. 121

repressive influence exercised by Cuvier's great authority.
In no civilized country of Europe has Darwin's doctrine
had so little effect and been so little understood as in
France. The Academy of Sciences in Paris on several
occasions even rejected the proposal to invite Darwin to
become a member, before it declared itself worthy of this
highest of honours. Among the recent French naturalists
(before Darwin) there are only two distinguished botanists
whom we may mention as having ventured to express
themselves in favour of the mutability and transformation
of species. These two men are Naudin (1852) and Lecoq
(1854).

Having discussed the early services of German and
French nature-philosophy in establishing the doctrine of
descent, we turn to the third great country of Europe, to
England, which, since the year 1859, has become the
chief seat and starting-point for the further working out
and definite establishment of the theory of development.
Englishmen at the beginning of the century took but
little part in the continental nature-philosophy and its
most important progress, the Theory of Descent. Almost
the only earlier English naturalist whom we have here
to mention is Erasmus Darwin, the grandfather of the
reformer of the Theory of Descent. In 1794 he published,
under the title of " Zoonomia," a scientific work in which
he expresses views very similar to those of Goethe and
Lamarck, without, however, then knowing anything
about these two men. It is evident that the Theory of
Descent at that time pervaded the intellectual atmosphere.
Erasmus Darwin lays great stress upon the transformation
of animal and vegetable species by their own vital

122 THE HISTORY OF CREATION.

action and by their becoming accustomed to changed
conditions of existence, etc. Next, W. Herbert, in 1822,
expressed the opinion that species of animals and plants
are nothing but varieties which have become permanent.
In like manner Grant, in Edinburgh, in 1826, declared that
new species proceed from existing species by continued
transformation. In 1841 Freke maintained that all organic
beings must be descended from a single primitive type. In
1852 Herbert Spencer demonstrated minutely, and in a very
clear and philosophic manner, the necessity of the Doctrine
of Filiation, and established it more firmly in his excellent
" Essays," which appeared in 1858, and in his " Principles of
Biology," which was published at a later date. He has, at
the same time, the great merit of having applied the theory
of development to psychology, and of having shown that the
emotional and intellectual faculties could only have been
acquired by degrees and developed gradually. Lastly, we
have to mention that in 1859 Huxley, the first of English
zoologists, spoke of the Theory of Descent as the only
hypothesis of creation reconcilable with scientific physiology.
The same year produced the " Introduction to the Flora
of Tasmania," in which Hooker, the celebrated English
botanist, adopts the Theory of Descent, supporting it with
important observations of his own.

All the naturalists and philosophers with whom we have
become acquainted in this brief historical survey, as men
adopting the Theory of Development, merely arrived at the
conception that all the different species of animals and
plants which at any time have lived, and still live, upon
the earth, are the gradually changed and transformed de-
scendants of one or some few original and very simple

DARWIN'S THEORY OF SELECTION. 1 23

prototypes, which latter arose out of inorganic matter by
spontaneous generation. But none of them succeeded in
placing this fundamental element of the doctrine of descent
in relation with some cause, nor in satisfactorily explaining
the transformation of organic species by the true demonstra-
tion of its mechanical antecedents. Charles Darwin was
the first who solved this most difficult problem, and this
forms the broad gulf which separates him from his pre-
decessors.

The special merit of Charles Darwin is, in my opinion,
twofold : in the first place, the doctrine of descent, the
fundamental idea of which was already clearly expressed
by Goethe and Lamarck, has been developed by him much
more comprehensively, has been traced much more minutely
in all directions, and carried out much more strictly and
connectedly than by any of his predecessors ; and secondly,
he has established a new theory, which reveals to us the
natural causes of organic development, the acting causes
(causae efficientes) of organic form-production, and "of the
changes and transformations of animal and vegetable species.
This is the Theory of Natural Selection (selectio naturalis).

When we reflect that almost the whole science of Biology,
before Darwin's time, was elaborated in accordance with
the opposite views, and that almost all zoologists and
botanists regarded the absolute independence of organic
species as a self-evident inference from the results of
all study of forms, we shall certainly not lightly value
the twofold merit of Darwin. The false doctrine of the
constancy and independent creation of individual species
had gained such high authority, was so generally recog-
nized, and was, moreover, so much favoured by delusive

124 THE HISTOEY OP CREATION.

appearances, accepted by superficial observation, that,
indeed, no small degree of courage, strength, and intelli-
gence was required to rise as a reformer against its
omnipotence, and to dash to pieces the structure artificially
erected upon it. But, in addition to this, Darwin added to
Lamarck's and Goethe's doctrine of descent the new and
highly important principle of " natural selection."

We must sharply distinguish the two points — though this
is usually not done — first, Lamarck's Theory of Descent,
which only asserts that all animal and vegetable species are
descended from common, most simple, and spontaneously
generated prototypes; and secondly, Darwin's Theory of
Selection, which shows us why this progressive transfor-
mation of organic forms took place, and what causes, acting
mechanically, effected the uninterrupted production of new
forms, and the ever-increasing variety of animals and plants.
Darwin's immortal merit cannot be justly estimated until
a later period, when the Theory of Development, after over-
throwing all other theories of creation, will be recognized as
the supreme principle of explanation in Anthropology, and,
consequently, in all other sciences. At present, while in
the hot contest for truth, the name of Darwin is the watch-
word to the advocates of the natural theory of development,
his merits are often inaccurately appreciated on both sides,
for some persons over-estimate them as much as others
under-estimate them.

His merit is over-estimated when he is regarded as the
founder of the Theory of Descent, or of the whole of the
Theory of Development. We have seen, from the historical
sketch in this and the preceding chapters, that the Theory
of Development, as such, is not new ; all the philosophers

LOUIS AGASSIZ ON DARWINISM. 125

who refused to be led captive by the blind dogma of a
supernatural creation were compelled to assume a natural
development. But even the Theory of Descent, as the
specially biological part of the universal Theory of Develop-
ment, had already been so clearly expressed by Lamarck,
and carried out so fully by him to its most important con-
sequences, that we must honour him as the real founder of
it. Hence it is only the Theory of Selection, and not that
of Descent, which may be called Darwinism ; but this is
in itself of so much importance, that its value can scarcely
be over-estimated.

Darwin's merit is naturally under-estimated by all his
opponents. But it is scarcely possible in this matter to
point to scientific opponents who are entitled by profound
biological culture to pronounce an opinion. For among all
the works opposed to Darwin and the Theory of Descent yet
published, with the exception of that of Agassiz, not one
deserves consideration, much less refutation ; all have so
evidently been written either without thorough knowledge
of biological facts, or without a clear philosophical under-
standing of the question in hand. We need not trouble
ourselves at all about the attacks of theologians and other
unscientific men, who really know nothing whatever of
nature.

The most eminent and most determined of Darwin's
scientific adversaries, and the whole theory of development,
was Louis Agassiz ; but the principle of his opposition in
reality deserves notice only as a philosophical curiosity. In
a French translation of his " Essay on Classification," which
we have spoken of before, published in Paris in 1869,
* Agassiz has most formally announced his opposition to

126 THE HISTOBY OP CEEATION.

Darwinism, which he had previously expressed in many
ways. To this translation he has appended a treatise of
sixteen pages, bearing the title, "Le Darwinisme. Classifi-
cation de Haeckel." This curious chapter contains the most
wonderful things; as, for example, "Darwin's idea is a
conception a priori. Darwinism is a burlesque of facts. . . .
Darwinism shuts out almost the whole mass of acquired
knowledge in order to retain and assimilate to itself that
only which may serve its doctrine."

Surely this is what we may call turning the whole affair
topsy-turvy ! The biologist who knows the facts must be
astounded at Agassiz's courage in uttering such sentences —
sentences without a word of truth in them, and which he
cannot himself believe ! The impregnable strength of the
Theory of Descent lies just in the fact that all biological
facts are explicable only through it, and that without it
they remain unintelligible miracles. All our "acquired
knowledge " in comparative anatomy and physiology — in
embryology and palseontology — in the doctrine of the
geographical and topographical distribution of organisms,
etc., constitutes an irrefutable testimony to the truth of the
Theory of Descent.

With the death of Louis Agassiz in December, 1873, the
last opponent of Darwinism, worthy of any scientific
consideration, was laid in his grave. His last work on the
Development and Permanence of the type was published
after his death in the Atlantic Monthly for January, 1874 ;
it is directed specially against Darwin's ideas and my
phylogenetic theories. However, Agassiz does not touch
the actual kernel of the matter. The extraordinary weak-
ness of this last attempt of his proves more clearly than

THE LAST WOEK OF AGASSIZ. 127

anything that the ammunition of our adversaries is
exhausted. In my General Morphology, especially in the
sixth book (in the General Phylogeny), I have minutely
refuted Agassiz's " Essay on Classification " in all essential
points. The twenty-fourth chapter I have devoted to
a very detailed and strictly scientific discussion of that
section which Agassiz himself considers the most important
(the groups or categories of systematic zoology and botany),
and think I have shown that this part of his work is purely
chimerical, without any trace of real foundation. Agassiz
took good care not to venture anywhere to touch upon my
refutation, because, forsooth, he was not in a position to
produce anything substantial against it. He fought not
with arguments, but with phrases. However, such opposi-
tion will not delay the complete victory of the Theory of
Development, but only accelerate it.

128 THE HISTORY OF CREATION.

CHAPTER VI.

THEORY OP DEVELOPMENT ACCORDING TO LYELL
AND DARWIN.

Charles Lyell's Principles of Geology. — His Natural History of the Earth's
Development. — Origin of the Greatest Effects through the Multiplica-
tion of the Smallest Causes. — Unlimited Extent of Geological Periods. —
Lyell's Refutation of Cuvier's History of Creation. — The Establishment
of the Uninterrupted Connection of Historical Development by Lyell
and Darwin. — Biographical Notice of Charles Darwin. — His Scientific
Works. — His Theory of Coral Reefs. — Development of the. Theory of
Selection. — A Letter of Darwin's. — The Contemporaneous Appear-
ance of Darwin's and Alfred Wallace's Theory of Selection. — Darwin's
Study of Domestic Animals and Cultivated Plants. — Andreas Wagner's
notions as to the Special Creation of Cultivated Organisms for the
Good of Man. — The Tree of Knowledge in Paradise.— Comparison
between Wild and Cultivated Organisms. — Darwin's Study of Domestic
Pigeons. — Importance of Pigeon-breeding. — Common Descent of all
Races of Pigeons*

During the thir y years, from 1830 until 1859, when
Darwin's work appeared, the ideas of creation introduced
by Cuvier remained predominant in the sciences of organic
nature. People rested satisfied with the unscientific assump-
tion, that in the course of the earth's history, a series of
inexplicable revolutions had periodically annihilated the
whole world of animals and plants, and that at the end of
each revolution, and the beginning of a new period, a new,

LYELL'S PRINCIPLES OF GEOLOGY. 1 29

enlarged, and improved edition of the organic population had
appeared. Although the number of these editions of creation
was altogether problematical, and in truth could not be fixed
at all, and although the numerous advances which, during
this time, were made in all the departments of zoology and
botany demonstrated more and more that Cuvier's hypo-
thesis was unfounded and untenable, and that Lamarck's
natural theory of development was nearer the truth, yet the
former maintained its authority almost universally among
biologists. This must, above all, be ascribed to the venera-
tion which Cuvier had acquired, and strikingly illustrates
how injurious to the progress of humanity a faith in
any definite authority may become. Authority, as Goethe
once admirably said, perpetuates the individual, which
as an individual should pass away, rejects and allows to
pass that which should be held fast, and is the main
obstacle to the advance of humanity.

It is only by having regard to the great weight of Cuvier's
authority, and to the mighty potency of human indolence,
which is with difficulty induced to depart from the broad
and comfortable way of everyday conceptions, and to enter
upon new paths not yet made easy, that we can comprehend
how it is that Lamarck's Theory of Descent did not gain
its due recognition until 1859, after Darwin had given it a
new foundation. The soil had long been prepared for it by
the works of Charles Lyell, another English naturalist,
whose views are of great importance for the natural history
creation, and must accordingly here be briefly explained.

In 1830 Charles Lyell published, under the title of "Prin-
ciples of Geology," a work in which he thoroughly re-
formed the science of Geology and the history of the earth's
VOL. I. K

130 THE HISTOBY OF CBEATION.

development, and effected this reform in a manner similar to
that in which, thirty years later, Darwin in his work re-
formed the science of Biology. Lyell's great treatise, which
radically destroyed Cuvier's hypothesis of creation, appeared
in the same year in which Cuvier celebrated his triumph
over the nature-philosophy, and established his supremacy
in the domain of morphology for the following thirty years.
Whilst Cuvier, by his artificial hypothesis of creation and
his theory of catastrophes connected with it, directly
obstructed the path of the theory of natural development,
and cut off all chance of a natural explanation, Lyell once
more opened a free road, and brought forward convincing
geological evidence to show that Cuvier's dualistic concep-
tions were as unfounded as they were superfluous. He
demonstrated that those changes of the earth's surface,
which are still taking place before our eyes, are perfectly
sufficient to explain everything we know of the development
of the earth's crust in general, and that it is superfluous and
useless to seek for mysterious causes in inexplicable revolu-
tions. He showed that we need only have recourse to the
hypothesis of exceedingly long periods of time in order to
explain the formation of the crust of the earth in the simplest
and most natural manner by means of the very same causes
which are still active. Many geologists had previously
imagined that the highest chains of mountains which rise
on the surface of the earth could owe their origin only to
enormous revolutions transforming a great part of the earth's
surface, especially to colossal volcanic eruptions. Such
chains of mountains as those of the Alps or the Cordilleras
were believed to have arisen direct from the fiery fluid of
the interior of the earth, through an enormous chasm in the

NECESSITY OE LONG PERIODS. 131

broken crust. Lyell, on the other hand, showed that we can
explain the formation of such enormous chains of mountains
quite naturally by the same slow and imperceptible risings
and depressions of the earth's surface which are still con-
tinually taking place, and the causes of which are by no
means miraculous. Although these depressions and risings
may perhaps amount only to a few inches, or at most a few
feet, in the course of a century ; still, in the course of some
millions of years they are perfectly sufficient to raise up the
highest chains of mountains, without the aid of mysterious
and incomprehensible revolutions. In like manner, the
meteorological action of the atmosphere, the influence of rain
and snow, and, lastly, the breakers on the coasts, which by
themselves seem to produce an insignificant effect, must
cause the greatest changes if we only allow sufficiently long
periods for their action. The multiplication of the smallest
causes produces the greatest effects. Drops of water produce
a cavity in a rock.

I shall afterwards be obliged again to recur to the im-
measurable length of geological periods which are necessary
for this purpose, for, as we shall see, Darwin's theory, as
well as that of Lyell, renders the assumption of immense
periods absolutely necessary. If the earth and its organisms
have actually developed in a natural way, this slow and
gradual development must certainly have taken a length of
time which surpasses our powers of comprehension. But as
many men see in this very circumstance one of the principal
difficulties in the way of those theories of development, I beg
leave here to remark that we have not a single rational
ground for conceiving the time requisite to be limited in any
way. Not only many ordinary persons, but even eminent

132 THE HISTORY OP CREATION.

naturalists, make it their chief objection to these theories, •
that they arbitrarily claim too great a length of time : yet
the ground of objection is scarcely intelligible. For it is
absolutely impossible to see what can, in any way, limit us
in assuming long periods of time. We have long known,
even from the structure of the stratified crust of the earth
alone, that its origin and the formation of neptunic rocks
from water must have taken, at least, several millions of
years. From a strictly philosophical point of view, it makes
no difference whether we hypothetically assume for this pro-
cess ten millions or ten thousand billions of years. Before
us and behind us lies eternity. If the assumption of such
enormous periods is opposed to the feelings of many, I regard
this simply as the consequence of false notions which are
impressed upon us from our earliest youth concerning the
short history of the earth, which is said to embrace only
a few thousands of years. Albert Lange, in his admirable
" History of Materialism," 12 has convincingly shown that
from a strictly philosophical point of view it is far less
objectionable in a scientific hypothesis to assume periods
which are too long than periods which are too short. Every
process of development is the more intelligible the longer it
is assumed to last. A short and limited period is the most
improbable.

I have no space here to enter minutely into Lyell's great
work, and will therefore mention only its most important
result, which is, that he completely refuted Cuvier's history
of creation with its mythical revolutions, and established in
its place the constant and slow transformation of the earth's
crust by the continued action of forces, which are still work-
ing on the earth's surface, viz. the movement of water and

CHARLES EOBEET DARWIN. 1 33

the volcanic fluid of the interior of earth. Lyell thus demon-
strated a continuous and uninterrupted connection of the
whole history of the earth, and he proved it so irrefutably,
and established so convincingly the supremacy of the " ex-
isting causes," that is, of the causes which are still active
in the transformation of the earth's crust, that Geology in
a short time completely renounced Cuvier's hypothesis.

Now, it is remarkable that Palaeontology, the science of
petrifactions, so far as it was pursued by botanists and zoolo-
gists, remained apparently unaffected by this great progress
in geology. Biology still continued to assume repeated new
creations of the whole animal and vegetable kingdoms, at
the beginning of every new period of the earth's history,
although this hypothesis of individual creations, shoved into
the world one after the other, without the assumption of
Cuvier's cataclysms, became pure nonsense, and lost its
foundation. It is evidently perfectly absurd to assume a
distinct new creation of the whole world of animals and
plants at definite epochs, without the crust of the earth
itself experiencing any considerable general revolution.
And although this conception is most closely connected
with Cuvier's theory of catastrophes, still it prevailed when
the latter had been completely destroyed and abandoned.

It was reserved for the great English naturalist, Charles
Darwin, to remove this contradiction, and to show that the
organic beings of the earth have a history as continuous and
connected as the inorganic crust of the earth ; that animals
and plants have arisen from one another by as gradual a
transmutation as that by which the varying forms of the
earth's crust, the forms of the continents, and of the seas
surrounding and separating them, have arisen out of earlier

134 THE HISTOEY OF CREATION.

and quite different forms. In this respect we may truly say
that in the domain of Zoology and Botany Darwin made
the same progress as Lyell, his great countryman, made in
the domain of Geology. Both proved the uninterrupted
connection of the historical development, and demonstrated !
a gradual transmutation of the different conditions succeed-
ing one another.

The special merit of Darwin, as I have already remarked
in a preceding chapter, is twofold. In the first place, he
has treated the Theory of Descent, put forth by Lamarck
and Goethe, in a much more comprehensive manner, as
a whole, and carried it out in a much more connected
manner, than had been done by any one of his predecessors.
Secondly, he has established the causal foundation of this
Theory of Descent by the Theory of Selection, which is
peculiarly his own ; that is, he has demonstrated the acting
causes of the changes which the Theory of Descent simply
stated, as facts. The Theory of Descent, introduced into
Biology in 1809, by Lamarck, asserts that all the different
species of animals and plants are descended from a single or
some few most simple prototypes, produced by spontaneous
generation. The Theory of Selection, established in 1859,
by Darwin, shows us why this must be so ; it points out
the acting causes in a manner with which Kant would
have been delighted, and indeed, in the domain of organic
nature, Darwin has become the Newton whose advent l
Kant thought himself entitled prophetically to deny.

Now, before we approach Darwin's theory, it will perhaps
be of interest to notice a few details as to the personal
character of this great naturalist, as to his life, and the
way in which he was led to form his doctrine. Charles

DARWIN'S LIFE. 135

Robert Darwin was born at Shrewsbury, on the Severn,
on the 12th of February, 1809 ; he died at his country
house at Down, in Kent, on the 19th of April, 1882, at the
age of seventy-three. In his seventeenth year (1825) he
entered the University of Edinburgh, and two years later
Christ's College, Cambridge. When scarcely twenty-two
years old, in 1831, he was invited to take part in a
scientific expedition which was sent out by England,
in order to survey accurately the southernmost point of
South America, and to examine several parts of the
South Seas. This expedition, like many other voyages of
inquiry fitted out in a praiseworthy manner by England,
had scientific objects, and at the same time was intended
to solve practical problems relating to navigation. The
vessel, commanded by Captain Fitzroy, appropriately bore
the symbolic name of the Beagle. The voyage of the
Beagle, which lasted five years, was of the highest im-
portance to the full development of Darwin's genius; for
in the very first year, when he set his foot on the soil
of South America, the "outline of the Doctrine of Descent
dawned upon him. Darwin himself has described this
voyage in a work which is written in a very attractive
style, and we obtain from it a brilliant picture of the
variously-gifted young naturalist. This book of travel,
which lies far above the usual average in interest, not only
shows in a very charming manner Darwin's amiable
character, but we can in many ways recognize the various
steps by which he arrived at his conceptions. The result of
the voyage was, first, a large scientific work, the zoological
and geological portion of which belong in a great measure
to Darwin ; and secondly, a celebrated work by him alone on

136 THE HISTOBY OF CREATION.

Coral Reefs, which in itself would have sufficed to secure to
him a lasting reputation. It is well known that the islands
in the South Seas consist for the most part of coral reefs,
and are surrounded by them. Formerly no satisfactory
explanation could be given of their different and remarkable
forms, and of their relation to those islands which are not
formed of corals. It was reserved for Darwin to solve this
difficult problem, for together with the constructive action
of the coral zoophytes, he assumed geological risings and
depressions of the bottom of the sea to account for the origin
of the different forms of reefs. Darwin's Theory of the
Origin of Coral Reefs, like his later one as to the Origin
of Organic Species, is a theory which fully explains the
phenomenon, and for this purpose assumes only the simplest
natural causes, without hypothetically supporting it with
any unknown processes. Among the remaining works of
Darwin, I must not pass over his excellent monograph on
the Cirrhipedia, a curious class of marine animals, which
in their outward appearance resemble mussels, and were
actually considered by Cuvier as Molluscs possessing two
shells, while in truth they belonged to the Crustacea (crabs).
After his return from his voyage in the Beagle, Darwin
resided for six years (between 1836 and 1842) partly in
London and partly in Cambridge, and in the winter of 1839
married his cousin, Emma Wedgewood. The extraordinary
hardships to which Darwin had been exposed during his five
years' voyage had injured his health to such a degree that
be was soon obliged to withdraw from the restless turmoil
of London life. In the autumn of 1842 he purchased an
estate close to the village of Down, near Bromley, in Kent.
There he lived for forty years in quiet retirement, till the

A LETTER FROM DARWIN. 1 37

end of his life, unwearied in the pursuit of scientific work.
The seclusion he enjoyed from the restless activity of
London life, his quiet intercourse with nature, and his
happy family life, helped to maintain his pleasure in and his
strength for work in spite of delicate health. Undisturbed
by the various engagements which in London would have
wasted his strength, he was enabled to concentrate his
attention upon the great problem to which his mind had
been turned during his voyage in the Beagle. In order to
show what kind of observations during the voyage prin-
cipally gave rise to the fundamental idea of the Theory of
Selection, and in what manner he afterwards worked it
out, I shall insert here a passage from a letter which he
addressed to me on the 8th of October, 1864.

Letter from Charles Darwin to Haeckel, 8th October, 1864.

" In South America three classes of facts were brought
strongly before my mind. Firstly, the manner in which
closely allied species replace species in going southward.
Secondly, the close affinity of the species inhabiting the
islands near South America to those proper to the con-
tinent. This struck me profoundly, especially the differ-
ence of the species in the adjoining islets in the Galopagos
Archipelago. Thirdly, the relation of the living Edentata
and Rodentia to the extinct species. I shall never forget
my astonishment when I dug out a gigantic piece of armour
like that of the living armadillo.

" Reflecting on these facts, and collecting analogous ones,
it seemed to me probable that allied species were descended
from a common parent. But for some years I could not
conceive how each form became so excellently adapted to

138 THE HISTORY OF CREATION.

its habits of life. I then began systematically to study
domestic productions, and after a time saw clearly that
man's selective power was the most important agent. I
was prepared, from having studied the habits of animals,
to appreciate the struggle for existence, and my work in
geology gave me some idea of the lapse of past time. There-
fore, when I happened to read 'Malthus on Population/
the idea of natural selection flashed on me. Of all the
minor points, the last which I appreciated was the im-
portance and cause of the principle of divergence."

During the leisure and retirement in which Darwin lived
after his return, he occtipied himself, as we see from this
letter, first and specially with the study of organisms in
their cultivated state; that is, domestic animals and garden
plants. This was undoubtedly the most likely way to
arrive at the Theory of Selection. In this, as in all his
labours, Darwin proceeded with extreme care and accuracy.
With wonderful caution and self-denial, he published nothing
on this subject during a period of twenty-one years, from
1837 to 1858, not even a preliminary sketch of his theory,
which he had written as early as 1844. He was always
anxious to collect still more certain experimental proofs, in
order to be able to establish his theory in a complete form,
and on the broadest possible foundation of experience.
While he was thus aiming at the greatest possible per-
fection, which might perhaps have led him never to publish
his theory at all, he was fortunately disturbed by a country-
man of his, who, independently of Darwin, had discovered
the Theory of Selection, and in 1858 sent its outlines to
Darwin himself, with the request to hand them to Lyell

DAKWIN'S VARIOUS WORKS. 1 39

for publication in some English journal. This was Alfred
Wallace, one of the boldest and most distinguished scientific
travellers of modern times. For many years Wallace had
wandered alone in the wilds of the Sunda Islands, in the
dense primitive forests of the Indian Archipelago; and
during this close and comprehensive study of one of the
richest and most interesting parts of the earth, with its
great variety of animals and plants, he had arrived at
exactly the same general views regarding the origin of
organic species as Darwin. Lyell and Hooker, both of
whom had long known Darwin's work, now induced him
to publish a short extract from his manuscripts simul-
taneously with the manuscript sent him by Wallace. They
appeared in the Journal of the Linnean Society, August, 1858.
Darwin's great work, " On the Origin of Species," in
which the Theory of Selection is carried out in detail,
appeared in November, 1859. Darwin himself, however,
characterizes this book (of which a sixth edition appeared
in 1872, and the German translation by Bronn as early as
I860) 1 as only a preliminary extract from a larger and
more detailed work, which would contain a mass of facts in
favour of his theory, and comprehensive and experimental
proofs. The first part of the larger work promised by
Darwin appeared in 1868, under the title, " The Variations
of Animals and Plants in the State of Domestication," and
has been translated into German by Victor Carus. 14 It con-
tains a rich abundance of the most valuable evidence as
to the extraordinary changes of organic forms which man
can produce by cultivation and artificial selection. How-
ever much we are indebted to Darwin for this abundance of
convincing facts, still we do not by any means share the

140 THE HISTORY OF CREATION.

opinion of those naturalists who hold that the Theory of
Selection requires for its actual proof these further details.
It is our opinion that Darwin's first work, which appeared
in 1859, already contains sufficient proof. The unassailable
strength of his theory does not lie in the immense amount
of individual facts that may be adduced as proofs, but in
the harmonious connection of all the great and general
phenomena of organic nature, which agree in bearing
testimony to the truth of the Theory of Selection.

Darwin, at first, intentionally did not notice the important
conclusion from his Theory of Descent, namely, the descent
of the human race from other mammals. It was not till
this highly important conclusion had been definitely estab-
lished by other naturalists as the necessary sequel of the
doctrine of descent, that Darwin himself expressly endorsed
it, and thereby completed his system. This was done in
the highly interesting work, "The Descent of Man, and
Sexual Selection," which appeared as late as 1871, and has
likewise been translated into German by Victor Carus. 48
Darwin's ingenious work on physiognomy, " The Expression
of the Emotions in Man and the Animals," which appeared
in 1872, may be considered a supplement to it.

The careful study which Darwin devoted to domestic
animals and cultivated plants was of the greatest impor-
tance in establishing the Theory of Selection. The infinitely
varied changes of form which man has produced in these
domesticated organisms by artificial selection are of the
very highest importance for a right understanding of animal
and vegetable forms ; and yet this study has, down to the
most recent times, been most grossly neglected by zoologists
and botanists. They have filled not only bulky volumes,

WAGNER ON THE CREATOR. 141

but whole libraries, with descriptions of individual species,
and with most] childish controversies as to whether these
species are good, or tolerably good, and bad, or tolerably
bad, without entering upon the discussion of the significance
to be attached to the idea of species itself. If naturalists,
instead of spending their time on these useless fancies, had
duly studied cultivated organisms, and had examined the
transmutation of the living forms, instead of the individual
dead ones, they would not have been led captive so long by
the fetters of Cuvier's dogma. But as cultivated organisms
are so extremely inconvenient to the dogmatic conception
of the permanence of species, naturalists to a great extent
intentionally did not concern themselves about them, and
even eminent naturalists have often expressed the opinion
that cultivated organisms, domesticated animals, and garden
plants are artificial productions of man, and that their
formation and transformation could not decide anything
about the nature of species and about the origin of the
forms of species that live in a natural state.

This perverse view went so far that, for example, Andreas
Wagner, a zoologist of Munich, quite seriously made the
following ridiculous assertion : " Animals and plants in
their wild state have been called into being by the Creator
as distinctly different and unchangeable species ; but in the
case of domestic animals and cultivated plants this was not
necessary, because he formed them from the beginning for
the use of man. The Creator formed man out of a clod of
earth, breathed the living breath into his nostrils, and then
created for him the different useful domestic animals and
garden plants, among which he thought well to save him-
self the trouble of distinguishing species." Unfortunately,

142 THE HISTOEY OF CREATION.

Andreas Wagner does not tell us whether the Tree of
Knowledge in Paradise was a " good " wild species, or, as a
cultivated plant, " no species " at all. As the Tree of Know-
ledge was placed by the Creator in the centre of Paradise,
we might be inclined to believe that it was a highly favoured
cultivated plant, and therefore no species at all. But since,
on the other hand, the fruit of the Tree of Knowledge was
forbidden to man, and since many men, as Wagner him-
self clearly shows, have never eaten of the fruit, it was
evidently not created for the use of man, and therefore in
all probability was a real species ! What a pity Wagner
has not given us any information about this important and
difficult problem !

Now, however ridiculous this view may appear to us, it
is only the logical sequence of a false view (which is widely
spread) of the special nature of cultivated organisms, and
one may occasionally hear similar objections from naturalists
of great reputation. I must most emphatically, and at once,
condemn this utterly false conception. It is the same per-
verseness which is committed by physicians who maintain
that diseases are artificial productions, and not natural
phenomena. It has been a work of hard labour to combat
this prejudice, and it is only in recent times that men have
generally adopted the view that diseases are nothing but
natural changes of the organisms, or really natural pheno-
mena of life, which are produced by changed and abnormal
conditions of existence. Disease, therefore, is not a life
beyond Nature's realm (vita prseter naturam), as the early
physicians used to say, but a natural life under conditions
which produce illness and threaten the body with danger.
Just in the same manner, cultivated organic forms are not

DOMESTICATED ORGANISMS. 143

artificial works of man, but natural productions which
have arisen under the influence of peculiar conditions of
life. Man by his culture can never directly produce a new
organic form, but he can breed organisms under new con-
ditions of life, which are such as to influence and transform
them. All domestic animals and all garden plants are
originally descended from wild species, which have been
transformed by the peculiar conditions of culture.

A thorough comparison of cultivated forms (races and
varieties) with organisms not altered by cultivation (species
and varieties) is of the utmost importance to the theory of
selection. What is most surprising in such a comparison is
the remarkably short time in which man can produce a
new form, and the high degree in which this form, pro-
duced by man, can deviate from the original form. While
wild animals and plants, one year after another, appear
to the zoologist and botanist approximately in the same
form, so as to have given rise to the false doctrine of the
constancy of species, domestic animals and garden plants,
on the other hand, display the greatest changes within a
few years. The perfection which gardeners and farmers
have attained in the art of selection now enables them, in
the space of a few years, arbitrarily to create entirely new
animal and -vegetable forms. For this purpose it is only
necessary to keep and propagate the organism under the
influence of special conditions — which are capable of pro-
ducing new formations — and even at the end of a few
generations new species may be obtained, which differ from
the original form in a much higher degree than so-called
good species in a wild state differ from one another. This
fact is extremely important, and we cannot lay sufficient

144 THE HISTOEY OF CREATION.

stress upon it. The assertion is not true that cultivated
forms descended from one and the same primary form do
not differ from one another as much as wild animal and
vegetable species differ among themselves. If only we
make comparisons, without prejudice, we can very easily
perceive that a number of races or varieties which have
been derived from a single cultivated form, within a short
series of years, differ from one another in a higher degree
than so-called good species (bonse species), or even different
genera of one family, in the wild state.

In order to establish this extremely important fact as
firmly as possible by experiments, Darwin decided to make
a special study of the whole extent of variation in form in
a single group of domesticated animals, and for this purpose
he chose the domestic pigeons, which are in many respects
especially suited for such a study. For a long time he kept
on his estate all possible races and varieties of pigeons
which he was able to procure, and he was helped in this
by rich contributions from all parts of the world. He also
joined two London pigeon clubs, the members of which
passionately, and with truly artistic skill, carry on the
breeding of the different forms of pigeons. Lastly, he
formed connections with some of the most celebrated
pigeon-fanciers; so that he could command the richest
experimental material.

The art of, and fancy for, pigeon-breeding is very ancient.
Even more than 3000 years before Christ, it was carried on
by the Egyptians. The Romans, under the emperors, laid
out enormous sums upon the breeding of pigeons, and kept
accurate pedigrees of their descent, just as the Arabs keep
genealogical pedigrees of their horses, and the Mecklenburg

VARIETIES OP PIGEONS. 1 45

aristocracy of their own ancestors. In Asia, too,, among
the wealthy princes, pigeon-breeding was a very ancient
fancy; in 1600, the court of Akber Khan possessed more
than 20,000 pigeons. Thus in the course of several centuries,
and in consequence of the various methods of breeding
practised in the different parts of the world, there has
arisen out of one single originally tamed form, an immense
number of different races and varieties, which in their most
divergent forms are extremely different from one another,
and are often curiously characterized.

One of the most striking races of pigeons is the well-
known fan-tailed pigeon, which spreads its tail like the
peacock, and carries a number of (from thirty to forty)
feathers placed in the form of radii, while other pigeons
possess much fewer tail feathers — generally twelve. We
may here .mention that the number of feathers on the tails
of birds is considered by naturalists of great value as a
systematic distinction, so that whole orders can thereby be
distinguished. For example, singing birds, almost with-
out exception, possess twelve tail feathers ; chirping birds
(Strisores) ten, etc. Several races of pigeons, moreover, are
characterized by a tuft of neck feathers, which form a kind
of periwig; others by grotesque transformation of their
beaks and feet, by peculiar and often very remarkable
decorations, as, for example, skinny lappets, which develop
on the head ; by a large crop, which is formed by the gullet
being strongly inclined forward, etc. Remarkable, also, are
the strange habits which many pigeons have acquired ; for
example, the turtle pigeons and the trumpeters with their
musical accomplishments, the carriers with their topo-
graphical instinct. The tumblers have the strange habit

vol. 1. L

146 THE HISTORY OF CREATIOK.

of ascending into the air in great numbers, then turning
over and falling down through the air as if dead. The
ways and habits of these endless races of pigeons — the
form, size, and colour of the individual parts of their bodies,
and their proportions, differ in a most astonishing degree
from one another ; in a much higher degree than is the
case with the so-called good species, or even with the per-
fectly distinct genera, of wild pigeons. And what is of the
greatest importance, is the fact that these differences are
not confined to the external form, but extend even to the
most important internal parts; there even occur great
modifications of the skeleton and of the muscular tissues.
For example, we find great differences in the number of
vertebrae and ribs, in the size and shape of the gaps in the
breast-bones, in the size and shape of the merry-thought, in
the lower jaw, in the facial bones, etc. In short, the bony
skeleton, which morphologists consider a very permanent
part of the body, and which never varies to such an extent
as the external parts, shows such great changes, that many
races of pigeons might be described as special genera, and
this would doubtless be done if all these different forms
had been found in a wild and natural state.

How far the differences of the races of pigeons have been
carried is best shown by the fact that all pigeon-breeders
are unanimously of opinion that each peculiar or specially
marked race of pigeons must be derived from a correspond-
ing wild original species. It is true every one assumes a
different number of original species. Yet Darwin has most
convincingly proved that all these pigeons, without ex-
ception, must be derived from a single wild primary species
— from the blue-rock pigeon (Colwmba livia). In like

VAEIETIES OF RABBITS. 1 47

manner, it can be proved of most of the domestic animals
and cultivated plants, that all the different races are
descendants of a single original wild species which has been
brought by man into a cultivated condition.

An example similar to that of the domestic pigeons is fur-
nished among mammals by our tame rabbit. All zoologists,
■without exception, have long considered it proved that all
its races and varieties are descended from the common wild
rabbit, that is, from a single primary species. And yet the
extreme forms of these races differ to such a degree from
one another, that every zoologist, if he met with them in a
wild state, would unhesitatingly designate them not only
as an entirely distinct " good species," but even as species
of entirely different genera of the Leporid family. Not
only does the colour, length of hair, and other qualities of
the fur of the different tame races of rabbits vary exceed-
ingly, and form extremely broad contrasts, but, what is still
more important, the typical form of the skeleton and its
individual parts do so also, especially the form of the skull
and the jaw (which is of such importance in systematic
arrangement) ; further, the relative proportion of the length
of the ears, legs, etc. In all these respects the races of
tame rabbits avowedly differ from one another far more
than all the different forms of wild rabbits and hares which
are scattered over all the earth, and are the recognized
" good species " of the genus Lepus. And yet, in the face
of these clear facts, the opponents of the theory of develop-
ment maintain that the wild species are not descended from
a common prototype, although they at once admit it in the
case of the tame races. With opponents who so intention-
ally close their eyes against the clear light of truth, no
further dispute can be carried on.

148 THE HISTORY OF CEEATION.

While in this manner it appears certain that the domestic
races of pigeons, of tame rabbits, of horses, etc., notwith-
standing the remarkable difference of their varieties, are
descended in each case from but one wild, so-called
" species ; " yet, on the other hand, it is certainly probable
that the great variety of races of some of the domestic
animals, especially dogs, pigs, and oxen, must be ascribed to
the existence of several wild prototypes, which have become
mixed. It is, however, to be observed that the number
of these originally wild primary species is always much
smaller than that of the cultivated forms proceeding from
their mingling and selection, and naturally they were
originally derived from a single primary ancestor, common
to the whole genus. In no case is each separate cultivated
race descended from a distinct wild species.

In opposition to this, almost all farmers and gardeners
maintain, with the greatest confidence, that each separate
race bred by them must be descended from a separate wild
primary species, because they clearly perceive the differences
of the races, and attach very high importance to the inherit-
ance of their qualities ; but they do not take into considera-
tion the fact that these qualities have arisen only by the
slow accumulation of small and scarcely observable changes.
In this respect it is extremely instructive to compare culti-
vated races with wild species.

Many naturalists, and especially the opponents of the
Theory of Development, have taken the greatest trouble
to discover some morphological or physiological mark, some
characteristic property, whereby the artificially bred and
cultivated races may be clearly and thoroughly distinguished
■ from wild species which have arisen naturally. All these

HYBRIDISM. I49

attempts have completely failed, and have led only with
increasing certainty to the result that such a distinction
is altogether impossible. I have minutely discussed this
fact, and illustrated it by examples in my criticism of the
idea of species (" Gen. Morph." ii. 323-364).

I may here briefly touch on yet another side of this
question, because not only the opponents, but even a few
of the most distinguished followers of Darwin — for example,
Huxley — have regarded the phenomena of bastard-breeding,
or hybridism, as one of the weakest points of Darwinism.
Between cultivated races and wild species, they say, there
exists this difference, that the former are capable of pro-
ducing fruitful bastards, but that the latter are not. Two
different cultivated races, or wild varieties of one species,
are said in all cases to possess the power of producing
bastards which can fruitfully mix with one another, or
with one of their parent forms, and thus propagate them-
selves ; on the other hand, two really different species, two
cultivated or wild species of one genus, are said never to
be able to produce from one another bastards which can be
fruitfully crossed with one another, or with one of their
parent species.

As regards the first of these assertions, it is simply
refuted by the fact that there are organisms which do not
mix at all with their own ancestors, and therefore can
produce no fruitful descendants. Thus, for example, our
cultivated guinea-pig does not bear with its wild Brazilian
ancestor ; and again, the domestic cat of Paraguay, which is
descended from our European domestic cat, no longer bears
with the latter. Between different races of our domestic
dogs, for example, between the large Newfoundland dogs

150 THE HISTOEY OF CREATION.

and the dwarfed lap-dogs, breeding is impossible, even for
simple mechanical reasons. A particularly interesting in-
stance is afforded by the Porto-Santo rabbit (Lepus Hux-
leyi). In the year 1419, a few rabbits, born on board ship
of a tame Spanish rabbit, were put on the island of Porto
Santo, near Madeira. These little animals, there being no
beasts of prey, in a short time increased so enormously that
they became a pest to the country, and even compelled a
colony to remove from the island. They still inhabit the
island in great numbers ; but in the course of four hundred
and fifty years they have developed into a quite peculiar
variety — or if you will have it, into a "good species"- —
which is distinguished by a peculiar colour, a rat-like shape,
small size, nocturnal life, and extraordinary wildness. The
most important fact, however, is that this new species,
which I call Lepus Huxleyi, no longer pairs with its
European parent rabbit, and no longer produces bastards
with it.

On the other hand, we now know of numerous examples
of fruitful genuine bastards ; that is, of mixings that have
proceeded from the crossing of two entirely different species,
and yet propagate themselves with one another as well as
with one of their parent species. A number of such bastard
species (species Hybridse) have long been known to botanists;
for example, among the genera of the thistle (Cirsium), the
laburnum (Cytisus), the bramble (Rubus), etc. Among
animals also they are by no means rare, perhaps even very
frequent. We know of fruitful bastards which have arisen
from the crossing of two different species of a genus, as
among several genera of butterflies (Zygsena, Saturnia), the
family of carps, finches, poultry, dogs, cats, etc. One of

FRUITFUL HYBRIDS. 151

the most interesting is the hare-rabbit (Lepus Darwinii),
the bastard of our indigenous hare and rabbit, many gene-
rations of which have been bred in France, since 1850, for
gastronomic purposes. I myself possess such hybrids, the
products of pure in-breeding, that is, both parents of which
are themselves hybrids by a hare-father and a rabbit-
mother. I possess them through the kindness of Professor
Conrad, who has repeatedly made these experiments in
breeding on his estate. The half-blood hybrid thus bred,
which I name in honour of Darwin, appears to propagate
itself through many generations by pure in-breeding, just
as well as any genuine species. Although on the whole it
is more like its mother (rabbit), still in the formation of
the ears and of the hind-legs, it possesses distinct qualities
of its father (hare). Its flesh has an excellent taste, rather
resembling that of a hare, though the colour is more like
that of a rabbit. But the hare (Lepus timidus) and the
rabbit (Lepus cuniculus) are two species of the genus Lepus,
so different that no systematic zoologist will recognize them
as varieties of one species. Both species, moreover, live in
such different ways, and in their wild state entertain so
great an aversion towards one another, that they do not
pair so long as they are left free. If, however, the newly-
born young ones of both species are brought up together,
this aversion is not developed ; they pair with one another
and produce the Lepus Darwinii.

Another remarkable instance of the crossing of different
species (where the two species belong even to different
genera !) is furnished by the fruitful hybrids of sheep and
goats which have for a long time been bred in Chili for in-
dustrial purposes. "What unessential circumstances in the

152 THE HISTOEY OF CREATION.

sexual mingling determines the fertility of the different
species is shown by the fact that he-goats and sheep in
their mingling produce fruitful hybrids, while the ram and
she-goat pair very rarely, and then without result. The
phenomena of hybridism, to which undue importance has
been erroneously attributed, are thus utterly unmeaning, so
far as the idea of species is concerned. The breeding of
hybrids does not enable us, any more than other phenomena,
thoroughly to distinguish cultivated races from wild species ;
and this circumstance is of the greatest importance in the
Theory of Selection,

( 153 )

CHAPTER VII.

THE THEORY OP SELECTION (DARWINISM).

Darwinism (Theory of Selection) and Lamarckism (Theory of Descent). —
The Process of Artificial Breeding. — Selection of the Different Indivi-
duals for After-breeding. — The Active Causes of Transmutation. —
Change connected with Food, and Transmission by Inheritance con-
nected with Propagation. — Mechanical Nature of these Two Physio-
logical Functions. — The Process of Natural Breeding : Selection in the
Struggle for Existence. — Malthus' Theory of Population. — The Propor-
tion between the Numbers of Potential and Actual Individuals of every
Species of Organisms. — General Struggle for Existence, or Competition
to attain the Necessaries of Life. — Transforming Force of the Struggle
for Existence. — Comparison of Natural and Artificial Breeding — Selec-
tion in the Life of Man. — Medical and Clerical Selection.

It is, properly speaking, not quite correct to designate the
whole Theory of Development, with which we are occupied
in these pages, as Darwinism. For, as we have seen from
the historical sketch in the previous chapters, the most
important foundation of the Theory of Development — that
is, the Doctrine of Filiation, or Descent — had already been
distinctly enunciated at the beginning of our century, and
had been definitely introduced into science by Lamarck.
The portion of the Theory of Development which maintains
the common descent of all species of animals and plants
from the simplest common original forms might, therefore,

r 54 THE HISTOEY OF CREATION.

in honour of its eminent founder, and with full justice, be
called Lamarckism, if the merit of having carried out such
a principle is to be linked to the name of a single dis-
tinguished naturalist. On the other hand, the Theory of
Selection, or breeding, might be justly called Darwinism,
being that portion of the Theory of Development which
shows us in what way and why the different species of
organisms have developed from those simplest primary
forms.

This Theory of Selection, or Darwinism in its proper sense,
to the consideration of which we now turn our attention,
rests essentially (as has already been intimated in the last
chapter) upon the comparison of those means which man
employs in the breeding of domestic animals and the culti-
vation of garden plants, with those processes which in free
nature, outside the cultivated state, lead to the coming into
existence of new species and new genera. We must there-
fore, in order to understand the latter processes, first turn
to the artificial breeding by man, as was, in fact, done by
Darwin himself. We must inquire into the results to which
man attains by his artificial breeding, and what means are
applied in order to obtain those results ; and we must then
ask ourselves, " Are there in nature similar forces and
causes acting similarly to those resorted to by man ? "

First, in regard to artificial breeding, we start from the
fact last discussed above, viz. that its products in some
cases differ from one another much more than the produc-
tions of natural breeding. It is a fact that races or varieties
often differ from one another in a much greater degree
and in much more important qualities than many so-called
species, or " good species," — nay, sometimes even more than

THE GAEDENEE'S SELECTION. 1 55

so-called " good genera " — in their natural state. Compare,
for example, the different kinds of apples which the art
of horticulture has derived from one and the same original
apple-form, or compare the different races of horses which
their breeders have derived from one and the same original
form of horse, and it will be easily observed that the
differences of the most different forms are extremely im-
portant, and much more important than the so-called
" specific differences," which are referred to by zoologists
and botanists when comparing wild forms for the purpose
of distinguishing several so-called " good species."

Now, by what means does man produce this extraordinary
difference or divergence of several forms which are proved
to be descended from the same primary form ? In order to
answer this question, let us follow a gardener who desires
to produce a new form of plant, which is distinguished by
the beautiful colour of its flowers. He will first of all make
a selection from a great number of plants which are seed-
lings from one and the same parent. He will pick out
those plants which exhibit most distinctly the colour of
flower he desires. The colour of flowers is a very change-
able thing. Plants, for example, which as a rule have a
white flower, frequently show deviations into the blue or
red. Now, supposing the gardener wishes to obtain the
red colour in a plant usually producing white flowers, he
will very carefully, from among the many different indi-
viduals which are the descendants of one and the same
seed-plant, select those which most distinctly show a reddish
tint, and sow them exclusively, in order to produce new
individuals of the same kind. He would cast aside and no
longer cultivate the other seedlings which show a white or

I5 6 THE HISTORY OF CREATION.

less distinct red colour. He will propagate exclusively the
individual plants whose blossoms show the red most
markedly, and he will sow the seeds produced by these
selected plants. From the seedlings of this second genera-
tion, he will again carefully select those in which the red,
which is now visible in the majority of them, is most dis-
tinctly displayed. If such a selection is carried on during
a series of six or ten generations, and if the flower which
shows the deepest red is most carefully selected, the
gardener in the sixth or tenth generation will obtain the
desired plants with flowers of a pure red.

The farmer wishing to breed a special race of animals,
for example, a kind of sheep distinguished by particularly
fine wool, proceeds in the same manner. The only process
applied in the improvement of wool consists in this, that
the farmer with the greatest care and perseverance selects
from a whole flock of sheep those individuals which have
the finest wool. These only are used in breeding, and
among the descendants of these selected sheep, those again
are chosen which have the finest wool, etc. If this careful
selection is carried'^ on through a series of generations, the
selected breeding-sheep are in the end distinguished by a
wool which differs very strikingly from the wool of the
original parent, and this is exactly the advantage which
the breeder desired.

The differences of the individuals that come into considera-
tion in this artificial selection are very slight. An ordinary
unpractised man is unable to discover the exceedingly
minute differences of individuals which a practised breeder
perceives at the first glance. The business of a breeder is
not easy; it requires an exceedingly sharp eye, great

CARE REQUIRED IN SELECTION. 157

patience, and an extremely careful manner of treating the
organisms to be bred. In each individual generation, the
differences of individuals are perhaps not seen at all by
the uninitiated ; but by the accumulation of these minute
differences during a series of generations, the deviation from
the original form becomes in the end very great. It becomes
so great that the artificially produced form may in the end
differ far more from the original form than do two so-
called "good species" in their natural state. The art of
breeding has now made such progress, that man can often at
discretion produce certain peculiarities in cultivated species
of animals and plants. To practised gardeners and farmers,
you may give distinct commissions, and say, for example,
I wish to have this species of plant with this or that colour,
and with this or that shape. Where breeding has reached
the perfection which it has attained in England, gardeners
and farmers are frequently able to furnish to order the
desired result within a definite period, that is, at the end of
a number of generations. Sir John Sebright, one of the
most experienced English pigeon-breeders, could assert that
in three years he would produce any form of feather, but
that he required six years to obtain any desired form of the
head and beak. In the process of breeding the merino- sheep
of Saxony, the animals are three times placed on a table
beside one another, and most carefully compared and studied.
Only the best sheep with the finest wool are selected, so
that in the end, out of a great multitude, there remain
only some few animals, but their wool is exquisitely fine,
and only these last are used in breeding. We see, there-
fore, that the causes through which, in artificial breeding,
great effects are produced, are unusually simple, and these

158 THE HISTORY OP CREATION.

great effects are obtained simply by accumulating the
differences which in themselves are very insignificant, and
become surprisingly increased by a continually repeated
selection.

Before we pass on to a comparison of this artificial with
natural breeding, let us see what natural qualities of the
organisms are made use of by the artificial breeder or
cultivator. We can trace all the different qualities which
here come into play to physiological fundamental qualities of
the organism, which are common to all animals and plants,
and are most closely connected with the functions of
'propagation and nutrition. These two fundamental quali-
ties are transmissibility , or the capability of transmitting
by inheritance, and mutability, or the capability of adapta-
tion. The breeder starts from the fact that all the indi-
viduals of one and the same species are different, even
though in a very slight degree, a fact which is as true of
organisms in a wild as in a cultivated state. If we lpok
about us in a forest consisting of only a single species of
tree, for example of beech, we shall certainly not find in the
whole forest two trees of this kind which are absolutely
identical or perfectly equal in the form of their branches, the
number of their branches and leaves, blossoms and fruits.
Special differences occur everywhere, just as in the ease of
men. There are no two men who are absolutely identical,
perfectly equal in size, in the formation of their faces, the
number of their hairs, their temperament, character, etc.
The very same is true of individuals of all the different
species of animals and plants. It is true that in most
organisms the differences are very trifling to the eye of the
uninitiated. Everything here essentially depends on the

UNIVERSALITY OF VARIATION. 1 59

exercise of the faculty of discovering these often very minute
differences of form. The shepherd, for example, knows every
individual of his flock, solely by accurately observing their
peculiarities, while the uninitiated are incapable of dis-
tinguishing at all the different individuals of one and the
same flock.

This fact of individual difference is the extremely im-
portant foundation on which the whole of man's power of
breeding rests. If individual differences did not exist every-
where, man would not be able to produce a number of
different varieties or races from one and the same original
stock. We must, at the outset, hold fast the principle that
the phenomenon is universal ; we must necessarily assume
it even where, with the imperfect capabilities of our senses,
we are unable to discover differences. Among the higher
plants (the phanerogams, or flower-plants), where the
individual stocks show such numerous differences in the
number of branches or leaves, and in the formation of the
stem and branches, we can almost always easily perceive
these differences. But this is not the case in the lower
plants, such as mosses, algse, fungi, and in most animals,
especially the lower ones. The distinction of all the indi-
viduals of one species is here, for the most part, extremely
difficult or altogether impossible. But there is no reason
for ascribing individual differences only to those organisms
in which we can perceive them at once. We may, on the
contrary, with full certainty assume such individuality as
a universal quality of all organisms, and we can do this all
the more surely since we are able to trace the mutability
of individuals to the mechanical conditions of nutrition.
By a mere change of nutrition we are able to produce

160 THE HISTORY OF CREATION.

striking individual differences where they would not exist
if the conditions of nutrition had not been altered. The
many complicated conditions of nutrition are never abso-
lutely identical in two individuals of a species.

Now, just as we see that the mutability or adaptability
has a causal connection with the general relations of nutri-
tion in animals and plants, so too we find the second
fundamental phenomenon of life, with which we are here
concerned, namely, the capability of transmitting by inherit-
ance, to have a direct connection with the phenomenon
of propagation. The second thing that a farmer or gardener
does in artificial breeding, after he has selected, and has
consequently availed himself of the mutability, is to en-
deavour to hold fast and develop the modified forms by
Inheritance. He starts from the universal fact that children
resemble their parents, that "the apple does not fall far
from the tree." This phenomenon of Inheritance has hitherto
been scientifically examined only to a very small extent,
which may partly arise from the fact that the phenomenon
is of such everyday occurrence. Every one considers it
quite natural that every species should produce its like;
that a horse should not suddenly produce a goose, or a
goose a frog. We are accustomed to look upon these every-
day occurrences of Inheritance as self-evident. But this
phenomenon is not so simply self-evident as it appears at
first sight, and in the examination of Inheritance the fact
is very frequently overlooked that the different descendants,
derived from one and the same parents, are in reality never
quite identical, and also never absolutely like the parents,
but are always slightly different. We cannot formulate the
principle of Inheritance, as "Like produces like," but we

ACQUIRED CHARACTERS TRANSMITTED. l6l

must limit the expression to "Similar things produce
similar things." The gardener, as well as the farmer,
avails himself of the fact of Inheritance in its widest form,
and indeed with special regard to the fact that not only
those qualities of organisms are transmitted by inherit-
ance which they have inherited from their parents, but
those also which they themselves have acquired. This
is an important point upon which very much depends. An
organism may transmit to its descendants not only those
qualities of form, colour, and size which it has inherited
from its parents, but it may also transmit variations of these
qualities, which it has acquired during its own life through
the influence of outward circumstances, such as climate,
nourishment, training, etc.

These are the two fundamental qualities of animals and
plants of which the breeder must avail himself in order to
produce new forms. The theoretical principle of breeding
is, indeed, extremely simple, but in detail the practical appli-
cation of this simple principle is difficult and immensely
complicated. A thoughtful breeder, acting according to
a definite plan, must understand the art of correctly esti-
mating, in every case, the general interaction between the
two fundamental qualities of hereditivity and mutability.

Now, if we examine the real nature of those two impor-
tant properties of life, we find that we can trace them, like
all physiological functions, to physical and chemical causes,
to the properties and the phenomena of motion of those
material particles of which the bodies of animals and plants
consist. As we shall hereafter have to show in the more
accurate consideration of these two functions, the trans-
mission by Inheritance, to express it quite generally, is

VOL. I. M

1 62 THE HISTORY OF CREATION.

essentially dependent upon the material continuity and
partial identity of the matter in the producing and produced
organism, the parents and the child. In every act of breed-
ing a certain quantity of protoplasm or albuminous matter
is transferred from the parents to the child, and along with
it there is transferred the peculiar molecular motion of the
individual. These molecular phenomena of motion in the
protoplasm, which call forth the phenomena of life, and are
their active and true cause, differ more or less in all living
individuals ; they are of infinite variety.

Adaptation, or deviation, is, on the other hand, essentially
the consequence of material influences, which the substance
of the organism experiences from the material surrounding
it, — from the conditions of life in the widest sense of the
word. The external influences of these conditions are com-
municated to the individual parts of the body by the mole-
cular processes of nutrition. In every act of Adaptation
the individual molecular motion of the protoplasm, peculiar
to each part, disturbs and modifies the whole individual, or
part of it, by mechanical, physical, or chemical influences.
The innate, inherited vital actions of the protoplasm — that
is, the molecular phenomena of motion of the smallest albu-
minous particles — are therefore more or less modified by it.
The phenomenon of Adaptation, or deviation, depends there-
fore upon the material influence which the organism ex-
periences from its surroundings, or its conditions of existence ;
while the transmission by Inheritance is due to the partial
identity of the producing and produced organism. These
are the real, simple, mechanical foundations of the artificial
process of breeding.

Now, Darwin asked himself, Does there exist a similar

THE STRUGGLE FOR EXISTENCE. 163

process of selection in nature, and are there forces in nature
which take the place of man's activity in artificial selection?
Is there a natural tendency among wild animals and plants
which acts selectingly, in a similar manner to the artificial
selection practised by the designing will of man ? All here
depended upon the discovery of such a relation, and Darwin
succeeded in this so satisfactorily, that we consider his
theory of selection completely sufficient to explain, mechani-
cally, the origin of the wild species of animals and plants.
That relation which in free nature influences the forms of
animals and plants, by selecting and transforming them, is
called by Darwin the " Struggle for Existence."

The " Struggle for Existence " has rapidly become a
watchword of the day. Yet this designation is, perhaps, in
many respects not very happily chosen, and the phenomena
might probably have been more accurately described as
" Competition for the Means of Subsistence." For under the
name of " Struggle for Life," many relations are compre-
hended which properly and strictly speaking do not belong
to it. As we have seen from the letter inserted in the
last chapter, Darwin arrived at the idea of the " Struggle
for Existence " from the study of Malthus' book " On the
Conditions and the Consequences of the Increase of Popula-
tion." It was proved in that important work, that the
number of human beings, on the average, increases in a
geometrical progression, while the amount of articles of food
increase only in an arithmetical progression. This dispro-
portion gives rise to a number of inconveniences in the
human community, which cause among men a continual
competition to obtain the necessary means of life, which
do not suffice for all.

1 64 THE HISTORY OF CREATION.

Darwin's theory of the struggle for life is, to a certain
extent, a general application of Malthus' theory of popula-
tion to the whole of organic nature. It starts from the
consideration that the number of possible organic indi-
viduals which might arise from the germs produced, is far
greater than the number of actual individuals which, in
fact, do simultaneously live on the earth's surface. The
number of possible or potential individuals is given us by
the number of the eggs and organic germs produced by
organisms. The number of these germs, from each of which,
under favourable circumstances, an individual might arise,
is very much larger than the number of real or actual
individuals — that is, of those that really arise from these
germs, come into life, and propagate themselves. By far the
greater number of germs perish in the earliest stage of life,
and it is only some favoured organisms which manage to
develop, and actually survive the first period of early youth,
and finally succeed in propagating themselves. This impor-
tant fact is easily proved by a comparison of the number of
eggs in a given species with the number of individuals which
exist of this species. These numerical relations show the
most striking contrast. There are, for example, species of
fowls which lay great numbers of eggs, and yet are among
the rarest of birds ; and the bird which is said to be the
commonest (the most widely spread) of all, the stormy petrel
(Proeellaria glacialis), lays only a single egg. The relation
is the same in other animals. There are many very rare
invertebrate animals, which lay immense quantities of eggs ;
and others again which produce only very few eggs, and yet
are among the commonest of animals. Take, for example,
the proportion which is observed among the human tape-

THE STRUGGLE FOE EXISTENCE 165

worms. Each tape-worm produces within a short period
millions of eggs, while man, in whom these tape- worms are
lodged, forms a far smaller number of eggs, and yet for-
tunately there are fewer tape-worms than human beings.
/In like manner, among plants there are many splendid
orchids, which produce thousands of seeds and yet are very
rare, and some kinds of asters (Compositse), which have but
few seeds, are exceedingly common.

This important fact might be illustrated by an immense
number of examples. It is evidently, therefore, not the
number of actually existing germs which indicates the num-
ber of individuals which afterwards come into life and
maintain themselves in life; but rather the case is this,
that the number of adult individuals is limited by other
circumstances, especially by the relations in which the
organism stands to its organic and inorganic surroundings.
Every organism, from the commencement of its existence,
struggles with a number of hostile influences : it struggles
against animals which feed on it, and to which it is the
natural food, against animals of prey and parasites ; it
struggles against inorganic influences of the most varied
kinds, against temperature, weather, and other circum-
stances ; but it also struggles (and this is much the most
important !), above all, against organisms most like and akin
to itself. Every individual, of every animal and vegetable
species, is engaged in the fiercest competition with every
other individual of the same species which lives in the same
place with it. In the economy of nature the means of sub-
sistence are nowhere scattered in abundance, but are very
limited, and far from sufficient for the number of organisms
which might develop from the germs produced. Therefore

1 66 THE HISTORY OF CREATION.

the young individuals of most species of animals and vege-
tables must have hard work in obtaining the means of
subsistence; this necessarily causes a competition among
them in order to obtain the indispensable supplies of
life.

This great competition for the necessaries of life goes on
everywhere and at all times, among human beings and
animals as well as among plants ; in the case of the latter
this circumstance, at first sight, is not so clearly apparent.
If we examine a field which is richly sown with wheat,
we can see that of the numerous young plants (perhaps
some thousands) which shoot up on a limited space, only a
very small proportion preserve themselves in life. A com-
petition takes place for the space of ground which each plant
requires for fixing its root, a competition for sunlight and
moisture. And in the same manner we find that, among all
animal species, all the individuals of one and the same species
compete with one another to obtain these indispensable
conditions of existence in the wide sense of the word.
They are equally indispensable to all, but really fall to the
lot of only a few — "Many are called, but few are chosen."
The fact of the great competition is quite universal. We
need only cast a glance at human society, where this
competition exists everywhere, and in all the different
branches of human activity. Here, too, a struggle is
brought about by the free competition of the different
labourers of one and the same class. Here too, as every-
where, this competition benefits the thing, or the work,
which is the object of competition. The greater and more
general the competition, the more quickly improvements
and inventions are made in the branch of labour, and

SURVIVAL OP THE FITTEST. 1 67

the higher is the grade of perfection of the labourers
themselves.

The position of the different individuals in this struggle
for life is evidently very unequal. Starting from the
inequality of individuals, which is a recognized fact, we
must in all cases necessarily suppose that all the individuals
of one and the same species have not equally favourable
prospects. Even at the beginning they are differently placed
in this competition by their different strengths and abilities,
independently of the fact that the conditions of existence
are different, and act differently at every point of the earth's
surface. We evidently have an infinite combination of in-
fluences, which, together with the original inequality of the
individuals during the competition for the conditions of
existence, favour some individuals and prejudice others.
The favoured individuals will gain the victory over the
others, and while the latter perish more or less early, without
leaving any descendants, the former alone will be able to
survive and finally to propagate the species. As, therefore,
it is clear that in the struggle for life the favoured indi-
viduals succeed in propagating themselves, we shall (even as
the result of this relation) perceive in the next generation
differences from the preceding one. Some individuals of
this second generation, though perhaps not all of them, will,
by inheritance, receive the individual advantage by which
their parents gained the victory over their rivals.

But now — and this is a very important law of inheritance
—if such a transmission of a favourable character is con-
tinued through a series of generations, it is not simply trans-
mitted in the original manner, but it is constantly increased
and strengthened, and in a later generation it attains a

1 68 THE HISTORY OF CREATION.

strength which distinguishes this generation very essentially
from the original parent. Let us, for example, examine a
number of plants of one and the same species which grow
together in a very dry soil. As the hairs on the leaves of
plants are very useful for receiving moisture from the air,
and as the hairs on the leaves are very variable, the
individuals possessing the thickest hair on their leaves will
have an advantage in this unfavourable locality where the
plants have directly to struggle with the want of water, and
in addition to this have to compete with one another for
the possession of what little water there may be. These
alone hold out, while the others possessing less hairy leaves
perish ; the more hairy ones will be propagated, and th,eir
descendants will, on the average, be more distinguished by
their thick and strong hairs than the individuals of the first
generation. If this process is continued for several genera-
tions in one and the same locality, there will arise at last
such an increase of this characteristic, such an increase of
the hairs on the surface of the leaf, that an entirely new
species seems to present itself.

It must here be observed, that in consequence of the
interaction of all the parts of every organism, as a rule
one individual part cannot be changed without at the
same time producing changes in other parts. If, for
instance, in our imaginary example, the number of the
hairs on the leaves is greatly increased, a certain amount
of nourishment is thereby withdrawn from other parts ;
the material which might be employed to form flowers or
seeds is diminished, and a smaller size of the flower or
seed will then be the direct or indirect consequence of the
struggle for life, which in the first place only produced

ARTIFICIAL AND NATUBAL SELECTION. 169

a change in the leaves. Thus the struggle for life, in this
instance, acts as a means of selecting and transforming.
The struggle of the different individuals to obtain the
necessary conditions of existence, or, taking it in its widest
sense, the inter-relations of organisms to the whole of their
surroundings, produce mutations of form such as are pro-
duced in the cultivated state by the action of man's
selection.

This agency will perhaps "appear at first sight small and
insignificant, and the student will not be inclined to concede
to the action of such relations the weight which it in reality
possesses. I must therefore find space in a subsequent
chapter to put forward further examples of the immense
and far-reaching power of transformation exhibited in
natural selection. For the present I will confine myself to
simply once more comparing the two processes of artificial
and natural selection, and clearly explaining the agreement
and the differences of the two.

Both natural and artificial selection are quite simple,
natural, mechanical relations of life, which depend upon the
interaction of two physiological functions, namely, on Adap-
tation and Inheritance, functions which, as such, must again
be traced to the physical and chemical properties of organic
matter. The difference between the two forms of selection
consists in this : in artificial selection the will of man makes
the selection according to a plan, whereas in natural selection,
the struggle for life (that universal inter-relation of organ-
isms) acts without a plan, but otherwise produces quite the
same result, namely, a selection of a particular kind of indi-
viduals for propagation. The alterations produced by artifi-
cial selection are turned to the advantage of those who make

170 THE HISTORY OF CREATION.

the selection ; in natural selection, on the other hand, to the
advantage of the selected organism.

These are the most essential differences and agreements of
the two modes of selection ; it must, however, be further
observed that there is another difference, viz. in the duration
of time required for the two processes of election. Man in
his artificial selection can produce very important changes in
a very short time, while in natural selection similar results
are obtained only after a much longer time. This arises from
the fact that man can make his selection with much greater
care. Man is able with the greatest nicety to pick out indi-
viduals from a large number, drop the others, and to employ
only the privileged beings for propagation, which is not the
case in natural selection. In natural conditions, besides the
privileged individuals which first succeed in propagating
themselves, some few or many of the less distinguished indi-
viduals will propagate themselves by the side of the former.
Moreover, man can prevent the crossing of the original and
the new form, which in natural selection is often unavoid-
able. If such a crossing, that is, a sexual connection, of the
new variety with the original forms takes place, the off-
spring thereby produced generally returns to the original
character. In natural selection, such a crossing can be
avoided only when the new variety by migration separates
from the original and becomes isolated.

Natural selection therefore acts much more slowly; it
requires much longer periods than the artificial process of
selection. But it is an essential consequence of this differ-
ence, that the product of artificial selection disappears much
more easily, and that the new form returns rapidly to the
earlier one, which is not the case in natural selection. The

NECESSARY EFFICIENCY OF NATURAL SELECTION. \J\

new species arising from natural selection maintain them-
selves much more permanently, and return much less easily
to the original form, than is the case with products of artifi-
cial selection, and accordingly maintain themselves during a
much longer time than the artificial races produced by man.
But these are only subordinate differences, which are ex-
plained by the different conditions of natural and artificial
selection, and in reality are connected only with differences
in the duration of time. The nature of the transformation
and the means by which it is produced are entirely the
same in both artificial and natural selection.

The thoughtless and narrow-minded opponents of Darwin
are never tired of asserting that his theory of selection is a
groundless conjecture, or at least an hypothesis which has
yet to be proved. That this assertion is completely un-
founded, may be perceived even from the outlines of the
doctrine of selection which have just been discussed.
Darwin assumes no kind of unknown forces of nature, nor
hypothetical conditions, as the acting causes for the trans-
formation of organic forms, but solely and simply the
universally recognized vital activities of all organisms, which
we term Inheritance and Adaptation. Every naturalist
acquainted with physiology knows that these two phenomena
are directly connected with the functions of propagation
and nutrition, and, like all other phenomena of life, are
purely mechanical processes of nature, that is, they depend
upon the molecular phenomena of motion in organic matter.
That the interaction of these two functions effect a con-
tinual, slow transmutation of organic forms, is a necessary
result of the struggle for existence. But this, again, is no
more a hypothetical relation, nor one requiring a proof,

172 THE HISTORY OP CREATION.

than is the interaction of Inheritance and Adaptation. The
struggle for life is a mathematical necessity, arising from
the disproportion between the limited number of places in
nature's household, and the excessive number of organic
germs. The origin of new species is moreover greatly
favoured by the active or passive migrations of animals
and plants, which takes place everywhere and at all times,
without being, however, entitled to rank as necessary agents
in the process of natural selection.

The origin of new species by natural selection, or, what
is the same thing, by the interaction of Inheritance and
Adaptation in the struggle for life, is therefore a mathe-
matical necessity of nature which needs no further proof.
Whoever, in spite of the present state of our knowledge,
still seeks for proofs for the Theory of Selection, only
shows that he either does not thoroughly understand the
theory, or is not sufficiently acquainted with the biological
facts — has not the requisite amount of experimental know-
ledge in Anthropology, Zoology, and Botany.

As in the case of every great idea that marks an epoch,
Darwin's Theory of Selection had its forerunners at an
earlier date ; and it is again our great Konigsberg philo-
sopher, Immanuel Kant, in whom we find the first ideas
of this theory already a century before Darwin. As Fritz
Schultze has pointed out in his already quoted work on
" Kant und Darwin'' (1875), Kant, as early as the year 1757
(hence more than a century before the appearance of Darwin's
principal work), in his " Physical Geography " makes various
statements in which both the idea of a history of develop-
ment of organic species, as well as the assumption of the
importance of selection, adaptation, and inheritance, are

KANT AS DAEWIN'S FOEEETJNNEE. 1 73

distinctly maintained. Thus, for instance, in the following
passage : " We have to account for the fact of some hens
being white, by a change in food, air, and breeding ; for if
we select, from among a number of chickens of the same
parents, only such as are white, and breed from these, we
shall at last have a white race which will not readily show
variations." Again, in his treatise " On the Different Eaces
of Man " (1775), he says, " It was the question of the possi-
bility of establishing some permanent family trait by the
careful selection of special births, that gave rise to the idea
of breeding a race of men noble by nature, in whom, in
fact, intellect, stability, and uprightness of character had
become hereditary." And how important to Kant was the
principle of the Struggle for Existence is proved, among
others, by the following passage from his " Pragmatic
Anthropology " : " Nature has placed the germ of dissension
in the human race, and this becomes the means by which
the amelioration of the race is accomplished by progressive
culture. The inner and outward struggle is the impetus
wherewith man passes from a rude state of nature into
that of a citizen, just as in the case of a piece of machinery,
where two opposite forces thwart each other by friction,
but are nevertheless kept in motion by the blow or pull of
other forces."

The next earliest traces of the theory of selection after
those of Kant's, we find in a treatise of Dr. W. 0. Wells,
published in 1818, but which had been read before the
Royal Society as early as 1813, entitled " On a Woman of
the White Race, whose Skin partly resembled that of a
Negro." The author states that negroes and mulattoes are
distinguished from the white race by their immunity from

174 THE HISTORY OF CREATION.

certain tropical diseases. On this occasion he remarks that
all animals have a tendency to change up to a certain
degree, and that farmers, by availing themselves of this
tendency, and also by selection, improve their domestic
animals ; and then he adds that what is done in this latter
case " by art, seems to be done with equal efficiency, though
more slowly, by nature, in the formation of varieties of
mankind fitted for the country which they inhabit. Of
the accidental varieties of man which would occur among
the first few and scattered inhabitants of the middle regions
of Africa, some race would be better fitted than others to
withstand the diseases of the country. This race would
consequently multiply, while the others would decrease;
not only from their inability to sustain the attacks of
disease, but from their incapacity of contending with their
more vigorous neighbours. The colour of this more
vigorous race, I take for granted, from what has already
been said, would be dark. But, the same disposition to
form varieties still existing, a darker and ever darker race
would in the course of time occur; and as the darkest
would be best fitted for the climate, it would at length
become the most prevalent, if not the only race, in the
particular country in which it had originated."

Although Dr. Wells clearly expresses and recognizes the
principle of natural selection, yet it is applied by him only
to the very limited problem of the origin of human races,
and not at all to that of the origin of animal and vegetable
species. Darwin's great merit in ^having independently
developed the Theory of Selection, and having brought
it to complete and well-merited recognition, is as little
affected by this earlier and long-forgotten remark of Wells,

ARTIFICIAL SELECTION. 1 75

as by other fragmentary observations about natural selection
made by Patrick Matthew, and hidden in his book on
" Timber for Shipbuilding, and the Cultivation of Trees,"
which appeared in 1831. The celebrated traveller, Alfred
Wallace, who developed the Theory of Selection indepen-
dently of Darwin, and had published it in 1858, simul-
taneously with Darwin's first contribution, likewise stands
far behind his greater and elder countryman in regard to
profound conception, as well as to the extended application
of the theory. In fact, Darwin, by his extremely compre-
hensive and ingenious development of the whole doctrine,
has acquired a fair claim to see the theory connected with
his own name.

If, as we maintain, natural selection is the great active
cause which has produced the whole wonderful variety of
organic life on the earth, all the interesting phenomena of
human life must likewise be explicable from the same
cause. For man is, after all, only a most highly-developed
vertebrate animal, and all aspects of human life have their
parallels, or, more correctly, their lower stages of develop-
ment, in the animal kingdom. The whole history of
nations, or what is called " Universal History," must there-
fore be explicable by means of natural selection— must be
a physico-chemical process, depending upon the interaction
of Adaptation and Inheritance in the struggle for life.
And this is actually the case. And yet not only natural
selection, but artificial selection as well, is variously active
in the history of the world.

A remarkable instance of artificial selection in man, on a
great scale, is furnished by the ancient Spartans, among
whom, in obedience to a special law, all newly-born

176 THE HISTORY OF CREATION.

children were subject to a careful examination and selection.
All those that were weak, sickly, or affected with any
bodily infirmity, were killed. Only the perfectly healthy
and strong children were allowed to live, and they alone
afterwards propagated the race. By this means, the Spartan
race was not only continually preserved in excellent
strength and vigour, but the perfection of their bodies
increased with every generation. No doubt the Spartans
owed their rare degree of masculine strength and rough
heroic valour (for which they are eminent in ancient
history) in a great measure to this artificial selection.

Many tribes also among the Red Indians of North
America (who at present are succumbing in the struggle
for life to the superior numbers of the white intruders, in
spite of a most heroic and courageous resistance) owe their
rare degree of bodily strength and warlike bravery to a
similar careful selection of the newly-born children. Among
them, also, all children that are weak or affected with a,nj
infirmity are immediately killed, and only the perfectly
strong individuals remain in life, and propagate the race.
That the race becomes greatly strengthened, in the course
of very many generations, by this artificial selection cannot
in itself be doubted, and is sufficiently proved by many
well-known facts.

The opposite of this artificial selection of the wild Red-
skins and the ancient Spartans is seen in the individual
selection which is practised in modern civilized countries,
by the advances of medical science in our day. Although
still little able really to cure internal diseases, yet medical
men possess and practise more than they used to do the art
of prolonging life during lingering, chronic diseases for

CLERICAL SELECTION. 1 77

many years. Such ravaging evils as consumption, scrofula,
syphilis, and also many forms of mental disorders, are
transmitted by inheritance to a great extent, and trans-
ferred by sickly parents to some of their children, or even
to the whole of their descendants. Now, the longer the
diseased parents, with medical assistance, can drag on their
sickly existence, the more numerous are the descendants
who will inherit incurable evils, and the greater will be
the number of individuals, again, in the succeeding gene-
ration, thanks to that artificial "medical selection," who
will be infected by their parents with lingering, hereditary
disease.

A more dangerous and injurious form of selection even
than medical selection, is that momentous process which
we term " clerical selection," and which is practised by all
powerful and united hierarchies. In every country where
a centralized clerical body has exercised its destructive
influence for centuries upon the education of the young,
upon family life, and thus upon the principal foundations
of the national life, the sad consequences of this demoralizing
" clerical selection " are distinctly evident in the decay of
culture and morality. We need only look at Spain, at this
" most Christian " land in Europe ! It is most obvious that
the highest development of the power of the Roman
Catholic Church, during the Middle Ages, coincides with
the lowest decline of scientific inquiry and of morality in
general. For its priests, being bound by that refined and
immoral institution of celibacy, are obliged to seek admit-
tance into the sanctum sanctorum of family life; and by their
productivity there, transmit the immoral features of their
nature upon a comparatively large number of descendants.

vol. 1. N

178 THE HISTORY OF OREATIOK.

The Roman Catholic process of selection was powerfully-
encouraged by the Inquisition, which did its utmost to
remove all the nobler and better characters.

On the other hand, it must be remembered that other
forms of artificial selection in the civilized life of man
exercise a very favourable influence. How much this is
the case is at once evident in many relations of our advanced
civilization, and especially of the improved arrangements of
school life and education. And even capital punishment
acts beneficially as an artificial process of selection. The .
abolition of capital punishment is, indeed, still regarded by
many as a " liberal measure," and the most absurd reasons
for it are given in the name of a false species of " humanity " !
And yet capital punishment, for incorrigible and degraded
criminals, is not only just, but also a benefit to the better
portion of mankind. The v same benefit is accomplished by
destroying luxuriant weeds, for the prosperity of a well-
cultivated garden.

In the same way as by a careful rooting out of weeds,
light, air, and ground is gained for good and useful plants,
in like manner, by the indiscriminate destruction of all
incorrigible criminals, not only would the struggle for life
among the better portion of mankind be made easier, but
also an advantageous artificial process of selection would
be set in practice, since the possibility of transmitting their
injurious qualities by inheritance would be taken from
those degenerate outcasts.

Against the injurious influence of the various kinds of
artificial selection, we fortunately have a salutary counter-
poise, in the invincible and much more powerful influence
of natural selection, which prevails everywhere. For in

THE STKTJGGLE OP BBAINS. 1 79

the life of man, as well as in that of animals and plants, this
influence is the most important transforming principle, and
the strongest lever for progress and amelioration. The
result of the struggle for life is that, in the long run, that
which is better, because more perfect, conquers that which
is weaker and imperfect. In human life, however, this
struggle for life will ever become more and more of an
intellectual struggle, not a struggle with weapons of murder.
The organ which, above all others, in man becomes more
perfect by the ennobling influence of natural selection, is
the brain. The man with the most perfect understanding,
not the man with the best revolver, will in the long run be
victorious ; he will transmit to his descendants the qualities
of the brain which assisted him in the victory. Thus then
we may justly hope, in spite of all the efforts of retrograde
forces, that the progress of mankind towards freedom, and
thus to the utmost perfection, will, by the happy influence
of natural selection, become more and more a certainty.

180 THE HISTORY OF CREATIOtf.

CHAPTER VIII.

TBANSMISSION BY INHBBITANCE AND PBOPAGATION.

Universality of Inheritance and Transmission by Inheritance. — Special
Evidences of the same. — Human Beings with four, six, or seven
Fingers and Toes. — Porcupine Men. — Transmission . of Diseases, espe-
cially Diseases of the Mind. — Original Sin. — Hereditary Monarchies.—
Hereditary Aristocracy. — Hereditary Talents and Mental Qualities. —
Material Causes of Transmission by Inheritance. — Connection between
Transmission by Inheritance and Propagation. — Spontaneous Genera-
tion and Propagation. — Non-sexual or Monogonous Propagation. — Pro-
pagation by Self-division. — Monera and Amoebae. — Propagation by the
formation of Buds, by the formation of Germ-Buds, by the formation
of Germ-Cells. — Sexual or Amphigonous Propagation. — Formation of
Hermaphrodites. — Distinction of Sexes, or Gonoohorism. — Virginal
Breeding, or Parthenogenesis. — Material Transmission of Peculiarities
of both Parents to the Child by Sexual Propagation.

The reader has, in the last chapter, become acquainted
with natural selection according to Darwin's theory, as the
constructive force of nature which produces the different
forms of animal and vegetable species. By natural selection
we understand the interaction which takes place in the
struggle for life between the transmission by inheritance
and the mutability of organisms, between two physiological
functions which are innate in all animals and plants,
and which may be traced to other processes of life —
the functions of propagation and nutrition. All the dif-
ferent forms of organisms, which people are usually in-

HEREDIXTVITY AND INHERITANCE. l8l

clined to look upon as the products of a creative power,
acting for a definite purpose, we, according to the Theory
of Selection, can conceive as the necessary productions
of natural selection, working without a purpose, — as the
unconscious interaction between the two properties of
Mutability and Hereditivity. Considering the importance
which accordingly belongs to these vital properties of
organisms, we must examine them a little more closely, and
employ a chapter with the consideration of Transmission
by Inheritance.

Strictly speaking, we must distinguish between Heredi-
tivity (Transmissivity) and Inheritance (Transmission).
Hereditivity is the power of transmission, the capability of
organisms to transfer their peculiarities to their descendants
by propagation. Transmission by Inheritance, or Inheritance
simply, on the other hand, denotes the exercise of the
capability, the actual transmission.

Hereditivity and Transmission by Inheritance are such
universal, everyday phenomena, that most people do not
heed them, and but few are inclined to reflect upon the
operation and import of these phenomena of life. It is
generally thought quite natural and self-evident that every
organism should produce its like, and that children should
more or less resemble their parents. Heredity is usually
only taken notice of and discussed in cases relating to
some special peculiarity, which appears for the first time
an a human individual without having been inherited
and then is transmitted to his descendants. It shows
itself in a specially striking manner in the case of certain
diseases, and in unusual and irregular (monstrous) devia-
tions from the usual formation of the body.

1 82 THE HISTOEY OF CREATION.

Amongst these cases of the inheritance of monstrous
deviations, those are specially interesting which consist in
an abnormal increase or decrease of the number five in the
fingers or toes of man. It is not unfrequently observed in
families through several generations, that individuals have
six fingers on each hand, or six toes on each foot. Less fre-
quent is the number of four or seven fingers or toes. The
unusual formation arises at first from a single individual who,
from unknown causes, is born with an excess of the usual
number of fingers and toes, and transmits these, by inherit^
ance, to a portion of his descendants. In one and the same
family it has happened that, throughout three, four, or more!
generations, individuals have possessed six fingers and toes.
In a Spanish family there were no less than forty individuals
distinguished by this excess. The transmission of the sixth
finger or toe is not permanent or enduring in all cases,
because six-fingered people always intermarry again with
those possessing five fingers. If a six-fingered family were
to propagate by pure in-breeding, if six-fingered men were
always to marry six-fingered women, this characteristic
would become permanent, and a special six-fingered human
race would arise. But as six-fingered men usually marry
five-fingered women, and vice versa, their descendants for
the most part show a very mixed numerical relation, and
finally, after the course of some generations, revert again to
the normal number of five. Thus, for example, among eight
children of a six-fingered father and a five-fingered mother,
two children may have on both hands and feet six fingers
and toes, four children may have a mixed number, and two
children may have the usual number of five on both hands
and feet. In a Spanish family, each child except the

CASES OF INHERITANCE. 183

youngest had the number six on both hands and feet ; the
youngest, only, had the usual number on both hands and
feet, and the six-fingered father of the child refused to
recognize the last one as his own.

The power of inheritance, moreover, shows itself very
strikingly in the formation and colour of the human skin
and hair. It is well known how exactly the nature of the
complexion in many families — for instance, a peculiar soft
or rough skin, a peculiar luxuriance of the hair, a peculiar
colour and largeness of the eyes — is transmitted through
many generations. In like manner, peculiar local growths
or spots on the skin, the so-called moles, freckles, and other
accumulations of pigment which appear in certain places,
are frequently transmitted through several generations so
exactly, that in the descendants they appear on the same
spots on which they existed in the parents. The porcupine
men of the Lambert family, who lived in London last cen-
tury, are especially celebrated. Edward Lambert, born in
1717, was remarkable for a most unusual and monstrous
formation of the skin. His whole body was covered with
a horny substance, about an inch thick, which rose in the
form of numerous thorn-shaped and scale-like processes,
more than an inch long. This monstrous formation of the
outer skin, or epidermis, was transmitted by Lambert to his
sons and grandsons, but not to his granddaughters. The
transmission in this instance remained in the male line, as
is often the case. In like manner, an excessive develop-
ment of fat in certain parts of the body is often transmitted
only in the female line. I scarcely need call to mind how
exactly the characteristic formation of the face is trans-
mitted by inheritance ; sometimes it remains within the

1 84 THE HISTORY OF CREATION.

male, sometimes within the female line ; sometimes it is
blended in both.

The phenomena of transmission by inheritance of patho-
logical conditions, especially of the different forms of human
diseases, are very instructive and generally known. Diseases
of the respiratory organs, the glands, and of the nervous
system are specially liable to be transmitted by inheritance.
Very frequently there suddenly appears in an otherwise
healthy family a disease until then unknown among them ;
it is produced by external causes, by conditions of life causing
diseases. This disease, brought about in an individual by
external cause, is propagated and transmitted to his descend-
ants, and some or all of them then suffer from the same
disease. In case of diseases of the lungs, for instance in
consumption, this sad transmission by inheritance is well
known, and it is the same with diseases of the liver, with
syphilis, and diseases of the mind. The latter are specially
interesting. Just as peculiar characteristic features of man
— pride, ambition, frivolity, etc. — are transmitted to the
descendants strictly by inheritance, so too are the peculiar
abnormal manifestations of mental activity, which are
usually called fixed ideas, despondency, imbecility, and
generally '■' diseases of the mind." This distinctly and
irrefragably shows that the soul of man, just as the soul
of animals, is a purely mechanical activity, the sum of
the molecular phenomena of motion in the particles of the
brain, and that it is transmitted by inheritance, together
with its substratum, just as every other quality of the body
is materially transmitted by propagation.

When this exceedingly important and undeniable fact is
mentioned, it generally causes great offence, and yet in

INHEBITANCE OF CHARACTER. 1 85

reality it is silently and universally acknowledged. For
upon what else do the ideas of " hereditary sin," " hereditary
wisdom," and " hereditary aristocracy," etc., rest than upon
the conviction that the quality of the human mind is trans-
mitted by propagation — that is, by a purely material pro-
cess—through the body, from the parents to the descendants ?
The recognition of the great importance of transmission by
inheritance is shown in a number of human institutions, as,
for example, among many nations in the division into castes,
such as the castes of warriors, castes of priests, and castes
of labourers, etc. It is evident that the institution of such
castes originally arose from the notion of the great im-
portance of hereditary distinctions possessed by certain
families, which it was presumed would always be trans-
mitted by the parents to the children. The institution of
an hereditary aristocracy and an hereditary monarchy is
to be traced to the notion of a transmission of special
excellences. However, it is unfortunately not only virtues,
but also vices, that are transmitted and accumulated by
inheritance ; and if, in the history of the world, we compare
the different individuals of the different dynasties, we shall
everywhere find a great number of proofs of the transmission
of qualities by inheritance, but fewer of transmissions of
virtues than of vices. Look only, for example, at the Roman
emperors, at the Julii and the Claudii, or at the Bourbons
in France, Spain, and Italy ! j

In fact, scarcely anywhere could we find such a number
of striking examples of the remarkable transmission of
bodily and mental features by inheritance, as in the history
of the reigning houses in hereditary monarchies. This is
specially true in regard to the diseases of the mind pre-

1 86 THE HISTORY OF CKEATION.

viously mentioned. It is in reigning families that mental
disorders are hereditary in an unusual degree. Thus Esquirol,
distinguished for his knowledge of mental diseases, proved
that the number of insane individuals in the reigning houses
was, in proportion to the number among the ordinary popu-
lation, as 60 to 1 ; that is, that disorders of the brain occur
60 times more frequently in the privileged families of the
ruling houses than among ordinary people. If equally
accurate statistics were made of the hereditary nobility,
the result would probably be that here also we should
find an incomparably larger contingent of mental diseases
than among the common, ignoble portion of mankind.
This phenomenon can scarcely astonish us when we consider
what injury these privileged castes inflict upon them-
selves by their unnatural, one-sided education, and by their
artificial separation from the rest of mankind. By this
means many dark sides of human nature are specially deve-
loped and, as it were, artificially bred, and, according to
the laws of transmission by inheritance, are propagated
through series of generations with ever-increasing force and
dominance.

It is sufficiently obvious from the history of nations how,
in successive generations of many dynasties, the noble
solicitude for the most perfect human accomplishments
in science and art were retained and transmitted from
father to son ; and how, on the other hand, in many other
dynasties, for centuries a special partiality for sensuous
pleasures, for the profession of war, and for other rude
acts of violence, have been hereditary. In like manner,
talents for special mental activities are transmitted in
many families for generations, as, for instance, talent for

MATERIAL BASIS OF INHERITANCE. 187

mathematics, poetry, music, sculpture, the investigation of
nature, philosophy, etc. In the family of Bach there have
been no less than twenty-two eminent musicians. Of course
the transmission of such peculiarities of mind depends upon
the material process of reproduction, as does the transmission
of mental qualities in general. In this case again, the vital
phenomenon, the manifestation of force (as everywhere in
nature), is directly connected with definite relations in the
admixture of the material components of the organism. It
is this definite proportion and molecular motion of matter
which is transmitted by generation.

Now, before we examine the numerous, and in some cases
most interesting and important, laws of transmission by
inheritance, let us make ourselves acquainted with the
actual nature of the process. The phenomena of transmis-
sion by inheritance are generally looked upon as something
quite mysterious, as peculiar processes which cannot be
fathomed by natural science, and the causes and actual
nature of which cannot be understood. It is precisely in
such a case that people very generally assume supernatural
influences. But even in the present state of our physiology
it can be proved with complete certainty that all the
phenomena of inheritance are entirely natural processes,
that they are produced by mechanical causes, and that they
depend on the material phenomena of motion in the bodies
of organisms, which we may consider as a part of the
phenomena of propagation. All the phenomena of Heredity
and the laws of Transmission by Inheritance can be traced
to the material process of Propagation.

Every organism, every living individual, owes its exist-
ence either to an act of unparental or Spontaneous Gene-

loo THE HISTORY OF CREATION.

ration (Generatio Spontanea, Archigonia), or to an act of
Parental Generation or Propagation (Generatio Parentalis,
Tocogonia). In a future chapter we shall have to consider
Spontaneous Generation, or Archigony, by which only
organisms of the most simple kind, the monera, can be
produced. At present we must occupy ourselves with
Propagation, or Tocogony, a closer examination of which
is of the utmost importance for understanding transmission
by inheritance. Most of my readers probably only know
the phenomena of Propagation which are seen universally
in the higher plants and animals, the processes of Sexual
Propagation, or Amphigony. The processes of Non-sexual
Propagation, or Monogony, are much less generally known.
The latter, however, are far more suited to throw light
upon the nature of transmission by inheritance in con-
nection with propagation.

For this reason, we shall first consider only the phe-
nomena of non-sexual or monogonic propagation (Mono-
gonia). This appears in a variety of different forms, as for
example, self-division, formation of buds, the formation of
germ-cells or spores. It will be most instructive, first, to
examine the propagation of the simplest organisms known to
us, which we shall have to return to later, when considering
the question of spontaneous generation. These very simplest
of all organisms yet known, and which, at the same time,
are the simplest imaginable organisms, are the Monera living
in water; they are very small living corpuscles, which,
strictly speaking, do not at all deserve the name of organism.
For the designation " organism," applied to living creatures,
rests upon the idea that every living natural body is com-
posed of organs, of various parts, which fit into one another

Life history of a simplest organism

PI. I.

■i y/ vgf V V vSJM • W '

: HjppWpI ,i pi

Protomvxcu azcrantiaccb.

DISCOVERY OF THE MONEKA. 189

and work together (as do the different parts of an artificial
machine), in order to produce the action of the whole.
But of late years we have become acquainted with Monera,
organisms which are, in fact, not composed of any organs at
all, but consist entirely of shapeless, simple, homogeneous
matter. The entire body of one of these Monera, during
life, is nothing more than a shapeless, mobile little lump of
mucus or slime, consisting of an albuminous combination
of carbon. "We assume that this homogeneous mass has
a very complicated and fine molecular structure ; however,
this has not been proved either anatomically or with the
aid of the microscope. Simpler or more imperfect organisms
we cannot possibly conceive.

The first complete observations on the natural history
of a Moneron (Protogenes primordialis) were made by me
at Nice, in 1864. Other very remarkable Monera I
examined later (1866) in Lanzarote, one of the Canary
Islands, and in 1867 in the Straits of Gibraltar. The com-
plete history of one of these Monera, the orange-red
Protomyxa aurantiaca, is represented in Plate I., and its
explanation is given in the Appendix. I found some
curious Monera also (in 1869) in the North Sea, off the
Norwegian coast, near Bergen. Cienkowski has described
an interesting Moneron from fresh waters, under the name of
Vampyrella; Sorokin another,- under the name of Oloidium ;
Leidy a third, as Biomyxa ; Mereschkowski a fourth, as
Haeckelina, etc. And similar genuine Monera, without a
nucleus, have been observed recently by numerous other
naturalists (Gruber, Trinchese, Maggi, Biitschli, etc.). Hence
I set great value upon this discovery of mine, that has so
often been called into question, for the proof of the existence

1 9° THE HISTOBY OF CREATION.

of these plastides without a nucleus is of the utmost
importance to several fundamental points in our theory of
development. The body of these plastides consists of
absolutely nothing but shapeless plasma or protoplasm, that
is, of the same albuminous combination of carbon which,
in infinite modifications, is found in all organisms, as the
essential and never-failing seat of the phenomena of life.
I have given a detailed description and drawing of the
Bathybius and other Monera in my " Monographic der
Moneren," 1870, 15 from which the drawing in Fig. 9 is taken-
In a state of rest most Monera appear as small globules
of mucus or slime, invisible, or nearly so, to the naked eye ;
they are at most as large as a pin's head. When the
Moneron moves itself, there are formed on the upper surface
of the little mucous globule, shapeless, finger-like processes,
or very fine radiated threads ; these are the so-called false
feet, or pseudopodia. The false feet are simple, direct
continuations of the shapeless albuminous mass, of which
the whole body consists. We are unable to perceive
different parts in it, and we can give a direct proof of the
absolute simplicity of the semi-fluid mass of albumen, for
with the aid of the microscope we can follow the Moneron
as it takes in nourishment. When small particles suited
for its nourishment — for instance, small particles of decayed
organic bodies or microscopic plants and infusoria — acci-
dentally come into contact with the Moneron, they remain
hanging to the sticky semi-fluid globule of mucus, and
here create an irritation, which is followed by a strong afflux
of the mucous substance, and, in consequence, they become
finally completely inclosed by it, or are drawn into the
body of the Moneron by displacement of the several albu-

THE MONERA. 191

minous particles, and are there digested, being absorbed
by simple diffusion (endosmosis).

Just as simple as the process of nutrition is the propaga-
tion of these primitive creatures, which in reality we can
neither call animals nor plants. All Monera propagate them-
selves only in a non-sexual manner by monogony; and
in the simplest case, by that kind of monogony which we
place at the head of the different forms of propagation, that
is, by self-division. When such a little globule, for example
a Protamceba or a Protogenes, has attained a certain size
by the assimilation of foreign albuminous matter, it falls
into two pieces ; a pinching-in takes place, contracting the
middle of the globule on all sides, and finally leads to the
separation of the two halves (compare Fig. 1). Each half

Pig. 1. — Propagation of the simplest organism, a Moneron, by self-division.
A. The entire Moneron, a Protamceba. B. It falls into two halves by a
contraction in the middle. 0. Each of the two halves has separated from
the other, and now represents an independent individual.

then becomes rounded off, and now appears as an indepen-
dent individual, which commences anew the simple course
of the vital phenomena of nutrition and propagation. By
the separated half becoming gradually replaced by growth,
this regeneration destroys a part for the good of the whole.
In other Monera (Vampyrella and Glodium), the body in

192 THE HISTORY OF CREATION.

the process of propagation does not fall into two, but into
four equal pieces, and in others, again (Protomonas,
Protomyxa, Myxastrum), at once into a large number of
small globules of mucus, each of which again, by simple
growth, becomes like the parent body (Plate I.). Here it is
evident that the process of propagation is nothing but
a growth of the organism beyond its own individual limit
of size.

The simple method of propagation of the Moneron by self-
division is, in reality, the most universal and most widely
spread of all the different modes of propagation ; for by this
same simple process of division, cells also propagate them-
selves. Cells are those simple organic individuals, a large
number of which constitute the bodies of most organisms,
the human body not excepted. With the exception of the
organisms of the lowest order, which have not even the
perfect form of a cell (Monera), or during life only repre-
sent a single cell (like many Protista), the body of every
organic individual is composed of a great number of cells.
Every organic cell is to a certain degree an independent
organism, a so-called " elementary organism," or an " indivi-
dual of the first order." Every higher organism is, in
a measure, a society or a state of such variously shaped
elementary individuals, variously developed by division
of labour. 89 Originally every organic cell is only a single
globule of mucus, like a Moneron, but differing from it in
the fact that the homogeneous albuminous substance has
separated itself into two different parts, a firmer albu-
minous body, the cell-Jcernel (nucleus), and an external,
softer albuminous body, the cell-slime (protoplasma). Besides
this, many cells later on form a third (frequently absent)

EEPEODUCTION OF AMCEBA. 193

distinct part, inasmuch as they cover themselves with
a capsule, by exuding an outer pellicle or cell-membrane
(membrana). All other forms of cells, besides these, are of
subordinate importance, and are of no further interest to
us here.

Every organism composed of many cells was originally
a single cell, and becomes many-celled owing to the fact
that the original cell propagates itself by self-division, and
that the new individual cells originating in this manner
remain together, and by division of labour form a commu-
nity or a state. The forms and vital phenomena of all many-
celled organisms are merely the effect or the expression of
all the forms and vital phenomena of all the individual cells
of which they are composed. The egg, from which most
animals and plants are developed, is a simple cell.

Fig. 2. — Propagation of a single-celled organism, Amoeba sphaerococcus,
by self-division. A. The enclosed Amoeba, a simple globnlar cell consisting of
a lump of protoplasm (c), which contains a kernel (b) and a kernel speck (a) ,
and is surronnded by a cell-membrane or capsule. B. The free Amoeba,
which has bnrst and left the cyst or cell-membrane. C. It begins to divide
by its kernel forming two kernels, and by the cell-substance between the two
becoming contracted. D. The division is completed by the cell-substance
likewise falling into two halves (Da and Db) .

The single-celled organisms, that is, those which during
life retain the form of a single cell, for example, the Amoebae
(Fig. 2), as a rule propagate themselves in the simplest way

vol. 1. o

194 THE HISTORY OF CREATION.

by self-division. This process differs from the previously-
described self-division of the Moneron only in the fact that
at the commencement the firmer cell-kernel (nucleus) falls
into two halves, by a pinching-in at its middle. The two
young kernels separate from each other and act now as two
distinct centres of attraction upon the surrounding softer
albuminous matter, that is, the cell-substance (protopla3ma).
By this process finally the latter also divides into two
halves, and there now exist two new cells, which are like
the mother cell. If the cell was surrounded by a membrane,
this either does not divide at all, as in the case of egg-
cleavage (Fig. 3, 4), or it passively follows the active
pinching-in of the protoplasm ; or, lastly, every new cell
exudes a new membrane for itself.

The non-independent cells which remain united in com-
munities or states, and thus constitute the body of higher
organisms, are propagated in the same manner as are in-
dependent single-celled organisms, for example, Amoeba
(Fig. 2). Just as in that case, the cell with which most
animals and plants commence their individual existence,
namely, the egg, multiplies itself by simple division. When
an animal, for instance, a mammal (Figs. 3, 4), develops out

Fig. 3.— Egg of a mammal (a simple cell).
a. The small kernel speck or nucleolus (the so-
called germ-spot of the egg). ~b. Kernel or
nucleus (the so-called germ-bladder of the egg),
c. Cell-substance or protoplasm (the so-called
yolk of the egg), d. Cell-capsule or membrane
(membrane of the yolk) of the egg; called in
mammals, on account of its transparency, Mem-
brana pellucida.

of an egg, this process of development always begins by the
simple egg-cell (Fig. 3) forming an accumulation of cells

DIVISION OP EGG-CELLS.

195

(Fig. 4) by continued self-division. The outer covering, or
cell-membrane, of the globular egg remains undivided. First,

Fig. 4. — First commencement of the development of a mammal's egg, the
so-called " cleavage of the egg" (propagation of the egg-cell by repeated
self-division) . A. The egg, by the formation of the first furrow, falls into
two cells. B. These separate by division into four cells. C. The latter
have divided into eight cells. X>. By repeated division a globular accumu-
lation of numerous cells has arisen.

the cell-kernel of the egg (the so-called germical vesicle)
divides itself into two kernels, then follows the cell-sub-
stance (the yolk of the egg) (Fig. 4 A). In like manner,
the two cells, by continued self-division, separate into four
(Fig. 4 B), these into eight (Fig. 4 0), into sixteen, thirty-
two, etc., and finally there is produced a globular mass of
very numerous little cells (Fig. 4 D). These now, by further
increase and heterogeneous development (division of labour),
gradually build up the compound many-celled organism.
Every one of us, at the commencement of our individual de-
velopment, has undergone the very same process as that repre-
sented in Fig. 4. The egg of a mammal — represented in Fig.
3, and its development in Fig. 4 — might as well be that of a
man, as of an ape, dog, horse, or any other placental mammal.
Now, when we examine this simplest form of propa-
gation, this self-division, it surely cannot be considered
wonderful that the products of the division of the original
organism should possess the same qualities as the parental

196 THE HISTOEY OF CREATION.

individual. For they are parts or halves of the parental
organism, and the matter or substance in both halves
is the same, and as both the young individuals have
received an equal amount and the same quality of matter
from the parent individual, one can but consider it
natural that the vital phenomena, the physiological qualities
should be the same in both children. In fact, in regard to
their form and substance, as well as to their vital phenomena,
the two produced cells can in no respect be distinguished
from one another, or from the mother cell. They have
inherited from her the same nature.

But this same simple propagation by self-division is not
only confined to simple cells — it is the same also in the
higher many-celled organisms ; for example, in the coral
zoophytes. Many of them which exhibit a high complexity
of composition and organization, nevertheless, propagate
themselves by simple division. In this case the whole
organism, with all its organs, falls into two equal halves as
soon as by growth it has attained a certain size. Each half
again develops itself, by growth, into a complete individual.
Here, again, it is surely self-evident that the two products
of division will share the qualities of the parental organism,
as they themselves are in fact halves of that parent.

Next to propagation by division we come to propagation
by the formation of buds. This kind of monogony is
exceedingly widely spread. It occurs both in the case of
simple cells (though not frequently) and in the higher
organisms composed of many cells. The formation of buds
is universal in the vegetable kingdom, less frequent in the
animal kingdom. However, here also it occurs in the
tribe of Plant-like Animals, especially among the Coral

GEMMATION. 1 97

Zoophytes, and among the greater portion of the Hydroid
Polyps very frequently, further also among some worms
(Planarian Worms, Ring- Worms, Moss Animals, Tunicates).
Most branching animal-trees or colonies, which are exceed-
ingly like branching plants, arise like those plants, by the
formation of buds.

Propagation by the formation of buds (Gemmatio) is
essentially distinguished from propagation by division, in
the fact that the two organisms thus produced by budding
are not of equal age, and therefore at first are not of equal
value, as they are in the case of division. In division
we cannot clearly distinguish either of the two newly
produced individuals as the parental, that is as the producer,
because, in fact, both have an equal share in the composition
of the original parental individual. If, on the other hand,
an organism sends out a bud, then the latter is the child of
the former. The two individuals are of unequal size and of
unequal form. If, for instance, a cell propagates itself by
the formation of buds, we do not see the cell fall into two
equal halves, but there appears at one point of it a protube-
rance, which becomes larger and larger, more or less separates
itself from the parental cell, and then grows independently.
In like manner we observe in the budding of a plant or
animal, that a small local growth arises on a part of the
mature individual, which growth becomes larger and larger,
and likewise more or less separates itself from the parental
organism by an independence in its growth. The bud, after
it has attained a certain size, may either completely separate
itself from the parental individual, or it may remain con-
nected with it and form a stock or colony, whilst at the
same time its life may be quite independent of that of its

198 THE HISTORY OF CREATION.

parent. While the growth which starts the propagation, in
the ease of self-division, is a total one affecting the whole
body, it is in the formation of buds only partial, affecting
merely a portion of the parental organism. But here, also,
the bud — the newly produced individual which remains so
long most directly connected with the parental organism,
and which proceeds from it — retains the essential qualities
and the original tendency of development of its parent.

A third mode of non-sexual propagation, that of the
formation of germ-buds (Polysporogonia), is intimately
connected with the formation of buds. In the case of the
lower, imperfect organisms, among animals, especially in
the case of the Plant-like animals and Worms, we very fre-
quently find that in the interior of an individual composed
of many cells, a small group of cells separates itself from
those surrounding it, and that this small isolated group
gradually develops itself into an individual, which becomes
like the parent, and sooner or later comes out of it.
Thus, for example, in the body of the Fluke- worms (Tre-
matodes) there often arise numerous little bodies consisting
of many cells, that is germ-buds, or polyspores, which at
an early stage separate themselves completely from the
parent body, and leave it when they have attained a certain
stage of development.

The formation of germ-buds is evidently but little different
from real budding. But, on the other hand, it is connected
with a fourth kind of non-sexual propagation, which almost
forms a transition to sexual reproduction, namely, the
formation of germ-cells (Monosporogonia), which is often
briefly called formation of spores (sporogonia). In this case
it is no longer a group of cells, but a single cell, which

GERM-CELLS AND GERM-BUDS. 1 99

separates itself from the surrounding cells in the interior of
the producing organism, and which only becomes further
developed after it has come out of its parent. After this
germ-cell, or monospore (or, briefly, spore), has left the
parental individual, it multiplies by division, and thus
forms a many-celled organism, -which by growth and
gradual development attains the hereditary qualities of the
parental organism. This occurs very generally among lower
plants.

Although the formation of germ-cells very much resembles
the formation of germ-buds, it evidently and very essentially
differs from the latter, and also from the other forms of non-
sexual propagation which have previously been mentioned,
by the fact that only a very small portion of the producing
organism takes part in the propagation and, accordingly, in
the transmission by inheritance. In the case of self-division,
where the whole organism falls into two halves, in the
formation of buds, where a considerable portion of the whole
body, already more or less developed, separates from the
producing individual, we easily understand that the forms
and vital phenomena should be the same in the producing
and produced organism. It is much more difficult to under-
stand in the formation of germ-buds, and more difficult still
in the formation of germ-cells, how this very small, quite
undeveloped portion of the body, this group of cells, or this
single cell, not only directly takes with it certain parental
qualities into its independent existence, but also after its
separation from the parental individual develops into a
many-celled body, and in this repeats the forms and vital
phenomena of the original producing organism. This last
form of monogonic propagation — that of the germ-cells, or

200 THE HISTORY OB" CREATION.

spore-formation — leads us directly to a form of propagation
which is the most difficult of all to explain, namely, sexual
propagation.

Sexual or amphigonic propagation (Amphigonia) is the
usual method of propagation among all higher animals and
plants. It is evident that it has only developed, at a very
late period of the earth's history, from non-sexual propaga-
tion, and apparently in the first instance from the method
of propagation by germ-cells. In the earliest periods of the
organic history of the earth, all organisms propagated them-
selves in a non-sexual manner, as numerous lower organisms
still do, especially all those which are at the lowest stage of
organization, and which, strictly speaking, can be considered
neither as animals nor as plants, and which therefore, as
primary creatures, or Protista, are best excluded from both
the animal and vegetable kingdoms. And yet in the case
of many of the Protista, increase by self-division, or the
formation of spores, takes place only when it has been
preceded by the commingling of two individual cells.
This conjugation or copulation is the beginning of sexual
propagation, and is at present, as a rule, the only means of
the increase of individuals among the higher animals and
planta

In all the chief forms of non-sexual propagation mentioned
above — in fission, in the formation of buds, germ-buds, and
germ-cells — the separated cell or group of cells was able by
itself to develop into a new individual, but in the case of
sexual propagation the cell must first be fructified by
another generative substance. Two different cells, the male
seed-cell (sperma) and the female egg-cell, must commingle ;
and out of this newly produced cell (the stork-cell, Cytula)

SEXUAL DIFFERENTIATION. 201

arises the many-celled organism. These two different
generative substances, the male sperm and the female egg,
are either produced by one and the same individual
hermaphrodite (Hermaphroditismus), or by two different
individuals (sexual separation, Gonochorismus).

The simpler and earlier form of sexual propagation is
through double-sexed individuals (Hermaphroditismus). It
occurs in the great majority of plants, but only in a minority
of animals, for example, in the garden snails, leeches, earth-
worms, and many other worms. Every single individual
among hermaphrodites produces within itself materials of
both sexes — eggs and sperm. In most of the higher plants
every blossom contains both the male organ (stamens and
anther) and the female organs (style and germ). Every
garden snail produces in one part of its sexual gland eggs,
and in another part sperm. Many hermaphrodites can
fructify themselves; in others, however, copulation and
reciprocal fructification of both hermaphrodites is necessary
for causing the development of the eggs. By this reciprocal
action the disadvantages of in-breeding are avoided. This
latter case is evidently a transition to sexual separation.

Sexual separation (Gonochorismus), which characterizes
the more complicated of the two kinds of sexual reproduc-
tion, has evidently been developed from the condition of
hermaphroditism at a late period of the organic history of
the world. It is at present the universal method of propa-
gation of the higher animals, and occurs, on the other hand,
only in the minority of plants (for example, in many aquatic
plants, e.g. Hydrocharis, Vallisneria; and in trees, e.g.
Willows, Poplars). Every organic individual, as a non-
hermaphrodite (Gonochoristus), produces within itself only

202 THE HISTOEY OF CREATION.

one of two generative substances, either the male or the
female. The female individuals, both in animals and plants,
produce eggs or egg-cells. The eggs of plants in the case
of flowering plants (Phanerogama) are commonly called
" embryo sacs ; " in the case of flowerless plants (Crypto-
gama), "fruit-spores." J In animals, the male individual
secretes the fructifying sperm (sperma); in plants, the
corpuscles, which correspond to the sperm. In the Phane-
rogama, these are the pollen-grains, or flower-dust ; in the
Cryptogama, a sperm, which, like that of most animals,
consists of floating vibratile cells actively moving in a
fluid — the zoosperms, spermatozoa, or sperm-cells.

The so-called virginal reproduction (Parthenogenesis)
offers an interesting form of transition from sexual repro-
duction to the non-sexual formation of germ-cells (which
most resembles it); it has been demonstrated to occur in
many cases among Insects, especially by Siebold's ex-
cellent investigations. In this case germ-cells, which
otherwise appear and are formed exactly like egg-cells,
become capable of developing themselves into new indi-
viduals without requiring the fructifying seed. The most
remarkable and most instructive of the different partheno-
genetic phenomena are furnished by those cases in which
the same germ-cells, according as they are fructified or not,
produce different kinds of individuals. Among our common
honey bees, a male individual (a drone) arises out of the
eggs of the queen, if the egg has not been fructified; a
female (a queen, or working bee), if the egg has been fructi-
fied. It is evident from this, that in reality there exists
on wide chasm between sexual and non-sexual reproduc-
tion, but that both modes of reproduction are directly

SEXUAL DIFFERENTIATION. 203

connected. The parthenogenesis of Insects must probably
be regarded as a relapse from the sexual mode of propaga-
tion (possessed by the original parents of the insects) to the
earlier condition of non-sexual propagation. In any case,
however, sexual reproduction, both in plants and animals,
which seems such a wonderful process, has only arisen at
a later date out of the more ancient process of non-sexual
reproduction. In both cases heredity is a necessary part of
the phenomenon.

Moreover, the parthenogenesis of insects is not an original,
primary phenomenon, but a secondary one, which has arisen
from a diminution of the male sex; for some reason or
another the males became superfluous !

At all events, both in plants as well as in animals, sexual
propagation — which appears so wonderful a process — arose
only at a later period from the earlier form of non-sexual
propagation. In both cases inheritance forms a necessary
part in the phenomenon of reproduction. The commingling
of two homogeneous cells, which in the case of numerous
Protista leads to non-sexual propagation by self-division
or the formation of spores (sometimes as temporary con-
jugation, sometimes as permanent copulation), is the first
step towards Amphigony. The second step is the hetero-
geneous development or divergence of the two cells, their
division of labour and of form. The smaller and more agile
cell becomes the male sperm-cell, the larger and less agile
cell the female egg-cell. Both of them, on commingling,
transmit their own peculiarities to the common product.
This transmission becomes quite intelligible when we
examine the whole series of phenomena in connection.

204 THE HISTOEY OP CREATION.

CHAPTER IX.

LAWS OF TRANSMISSION BY INHERITANCE.

Theories of Inheritance. — Difference between Transmission by Inheritance
in Sexual and Non-sexual Propagation. — Distinction between Con-
servative and Progressive Transmission by Inheritance. — Laws of
Conservative Transmission : Transmission of Inherited Characters. —
Uninterrupted or Continuous Transmission. — Interrupted or Latent
Transmission. — Alteration of Generations. — Relapse. — Degeneracy. —
Sexual Transmission. — Secondary Sexual Characters. — Mixed or Amphi-
gonous Transmission. — Hybrids. — Abridged or Simplified Transmis-
sion. — Laws of Progressive Inheritance : Transmission of Acquired
Characters. — Adapted or Acquired Transmission. — Fixed or Established
Transmission. — Homochronous Transmission (Identity in time). —
Homotopic Transmission (Identity in place). — Molecular Theories of
Transmission. — Pangenesis (Darwin). — Perigenesis (Haeckel). — Idio-
plasma (Nageli). — Germ-plasma (Weismann). — Intracellular Pangenesis
(Vries).

The proper understanding of the two great organic
constructive forces of Inheritance and Adaptation are
among the most important advances which, during the last
thirty years, our modern theory of development has intro-
duced into the general history of nature. The very com-
plicate interaction of these two forces, together with the
ever-varying relations of the struggle for existence, is
sufficient for producing the whole variety of forms in the
organic world. The earlier school of naturalists, at the

LAWS OF TRANSMISSION. 205 ,

beginning of our century, did, indeed, recognize the immense
importance of this interaction, but they were unable to
penetrate further into the mysterious character of the two
"constructive forces." However, the grand advances in
morphology and physiology, in histology and ontogeny,
have now furnished us with a far deeper insight into their
true nature, and we know them to be genuine physiology
functions, i.e. universal vital forces in organisms them-
selves ; and like other vital processes these two fundamental
constructive forces proceed primarily from physical and
chemical relations. They certainly at times appear ex-
tremely complicate, but can nevertheless be traced back
to simple, mechanical causes, to the attraction and repul-
sion of particles of matter, of molecules and of atoms.

As I endeavoured to show in my " General Morphology "
(in 1866), we arrive at an understanding of Inheritance
from the complicate phenomena of propagation, whereas the
phenomena of Adaptation are explained by the elementary
conditions of nutrition, more especially by the trophic
irritation exercised on the one hand by the direct influence
of the external conditions of life, on the other by the
peculiar activity of the organs and of the cells of which
they are composed.

In my last chapter I endeavoured to show that in the
case of all the different forms of propagation (and also
of inheritance) the most essential point is invariably a
detachment from the parental organism of a portion
possessing the faculty of leading an individual, independent
existence. We may, therefore, in all cases expect that the
produced individuals — which are, in fact, as is commonly
said, " the flesh and blood of the parents " — will receive the

206 THE HISTORY OF CREATION.

vital characteristics and qualities of form which the
parental individuals possess. It is simply a larger or
smaller quantity of the parental material, in fact, of its
albuminous protoplasm, or cell-substance, which passes to
the produced individual. But together with the material,
its vital properties — that is, the molecular motions of the
plasma — are transmitted, and these then manifest themselves
in its form. Inheritance by sexual breeding loses very
much of the mysterious and wonderful character which it
at first sight possesses for the uninitiated, if we consider
the above-mentioned series of the different modes of pro-
pagation, and their connection one with another. It at
first sight appears exceedingly wonderful that in the sexual
propagation of man, and of all higher animals, the small
egg, the minute cell, often invisible to the naked eye, is
able to transfer to the produced organism all the qualities
of the material organism, and, no less mysterious, that at
the same time the essential qualities of the paternal
organism are transferred to the offspring by means of the
male sperm, which fructifies the egg-cell by means of a
viscid substance in which minute thread-like cells or zoo-
sperms move about. But as soon as we compare the con-
nected stages of the different kinds of propagation, in which
the produced organism separates itself more and more as a
distinct growth from the parental individual, and more or
less early enters upon its independent career; as soon as
we consider, at the same time, that the growth and develop-
ment of every higher organism only depends upon the
increase of the cells composing it — that is, upon their
simple propagation by division — it becomes quite evident
that all these remarkable processes belong to one series.

THE MATERIAL BASIS OF LIFE. 207

The life of every organic individual is nothing but a
connected chain of very complicated material phenomena
of motion. These motions must be considered as changes
in the position and combination of the molecules, that is,
of the smallest particles of animated matter (of atoms
united in the most varied ways). The specific, definite
tendency of this regular, continuous, and inherent vital
motion depends, in every organism, upon the chemical
mingling of the albuminous generative matter to which
it owes its origin. In man, as in the case of the higher
animals which propagate themselves in a sexual manner,
the individual vital motion commences at the moment
in which the egg-cell is fructified by the spermatic
filaments of the seed, in which process both generative
substances actually mix; and here the tendency of the
vital motion is determined by the specific, or, more
accurately, by the individual nature of the sperm as well
as of the egg. There can be no doubt as to the purely
mechanical, material nature of this process. But here we
stand full of wonder and astonishment before the infinite
and inconceivable delicacy of this albuminous matter. We
are amazed at the undeniable fact that the simple egg-cell
of the maternal organism, and a single paternal sperm-
thread, transfer the molecular, individual vital motion of
the two individuals to the child so accurately, that after-
wards the minutest bodily and mental peculiarities of both
parents reappear in it.

Here we stand before a mechanical phenomenon of
nature of which Virchow, whose genius founded the
"cellular pathology," says with full justice, "If the
naturalist cared to follow the custom of historians and

208 THE HISTORY OF CREATION.

preachers, and to clothe phenomena, which are in their way
unique, with the hollow pomp of ponderous and high-
sounding words, this would be the opportunity for him \
for we have now approached one of those great mysteries of
animal nature, which encircle the region of animal life as
opposed to all the rest of the world of phenomena. The
question of the formation of cells, the question of the ex-
citation of a continuous and equable motion, and finally
the questions of the independence of the nervous system and
of the soul — these are the great problems on which the
human mind can measure its strength. To comprehend the
relation of the male and female to the egg-cell is almost as
much as to solve all those mysteries. The origin and
development of the egg-cell in the mother's body, the trans-
mission of the bodily and mental peculiarities of the father
to it by his seed, touch upon all the questions which the
human mind has ever raised about man's existence." And,
we add, these most important questions are solved, by means
of the Theory of Descent, in a purely mechanical, a purely
monistic sense !

There can, therefore, be no further doubt that, in the
sexual propagation of man and all higher organisms, inherit-
ance, which is a purely mechanical process, is directly
dependent upon the material continuity of the producing
and produced organism, just as is the case in the simplest
non-sexual propagation of the lower organisms. However,
I must at once take this opportunity of drawing atten-
tion to an important difference which inheritance presents
in sexual and non-sexual propagation. It is a fact long
since acknowledged, that the individual peculiarities of the
producing organism are much more accurately transmitted

CUTTINGS AND SEEDLINGS. 20Q

to the produced organism by non-sexual than by sexual
propagation. Gardeners have for a long time made use
of this fact in many ways. When, for instance, a single
individual of a species of tree with stiff, upright branches
accidentally produces down-hanging branches, a gardener,
as a rule, cannot transmit this peculiarity by sexual, but
only by non-sexual propagation. The twigs cut off such a
weeping tree and planted as cuttings or slips, afterwards
produce trees having likewise hanging branches, as, for
example, the weeping willows and beeches. Seedlings, on
the other hand, which have been reared out of the seed of
such a weeping tree, generally have the original stiff and
upright form of branches possessed by their ancestors.
The same may be observed in a very striking manner in
the so-called "copper-coloured trees," that is, varieties of
trees which are characterized by a red or reddish brown
colour of the leaves. Off-shoots from such copper-coloured
trees (for example, the copper beech), which have been
propagated by cuttings in a non-sexual manner, show the
peculiar colour and nature of the leaves which distinguished
the parental individual, while others reared from seeds of
such a copper-coloured tree return to the green-coloured
condition of leaf.

This difference in inheritance will seem very natural when
we consider that the material connection between the pro-
ducing and produced individuals is much closer and lasts
much longer in non-sexual than in sexual propagation. The
special tendency of the molecular motion of life can there-
fore fix itself much longer and more thoroughly in the filial
organism, and be more strictly transmitted by non-sexual
than by sexual propagation. All these phenomena, con-

VOL. i. p

2IO THE -HISTORY OP CREATION".

sidered in connection, clearly prove that the transmission of
bodily and mental peculiarities is a purely material and
mechanical process. By propagation a greater or lesser
quantity of albuminous particles, and together with them
the individual form of motion inherent in these molecules
of protoplasm, are transmitted from the parental organism to
the offspring. As this form of motion remains continuous,
the more delicate peculiarities inherent in the parental
organism must sooner or later reappear in the filial
organism.

The most important task in the physiology of Inheritance
would therefore be to obtain a deeper insight into the
processes of these molecular movements, and to examine
more accurately the physio-chemical processes connected
with them, and to do this experimentally wherever possible.
However, the task is so exceedingly difficult, that not one
of the already mentioned theories of molecular inheritance
appears sufficient. However, before turning our attention
to them, it seems appropriate first to cast one more glance
at the various manifestations of Heredity, which we may
perhaps even now denominate the " laws of transmission
by inheritance," Unfortunately, up to the present time
very little has been done for this most important subject,
either in zoology or in botany ; professional physiologists
have hardly troubled themselves at all about the subject,
so that almost all we know of the different laws of inherit-
ance is confined to the experiences of gardeners and
farmers. It is not therefore to be wondered at, that on the
whole these exceedingly interesting and important pheno-
mena have not been investigated with desirable scientific
accuracy, or reduced to the form of scientific laws. Accord-

LAW OF INHERITANCE. 211

ingly, what I shall relate of the different laws of trans-
mission are only some preliminary fragments taken out of
the infinitely rich store which lies open to our inquiry.

We may first divide all the different phenomena of inherit-
ance into two groups, which we shall distinguish as the
transmission of inherited characters, and the transmission of
acquired characters ; and we may call the former the con-
servative transmission, and the latter the progressive trans-
mission by inheritance. This distinction depends upon the
exceedingly important fact that the individuals of every
species of animals and plants can transmit to their de-
scendants, not only those qualities which they themselves
have inherited from their ancestors, but also the peculiar,
individual qualities which they have acquired during their
own life. The latter are transmitted by progressive, the
former by conservative inheritance. We have now first to
examine the phenomena of conservative inheritance, that
is, the transmission of such qualities as the organism has
already received from its parents or ancestors.

Among the phenomena of conservative inheritance we are
first struck by that which is its most general law, and which
we may term the law of uninterrupted or continuous trans-
mission. It is so universal among the higher animals and
plants, that the uninitiated might over-estimate its action
and consider it as the only normal law of transmission by
inheritance. This law simply consists in the fact that
among most species of animals and plants, every generation
is, on the whole, like the preceding — that the parents are as
like the grandparents as they are like the children. " Like
produces like," as is commonly said, but more accurately,
" Similar things produce similar things." For, in reality, the

212 THE HISTORY OF CREATION.

descendants of every organism are never absolutely equal
in all points, but only similar in a greater or less degree.
This law is so generally known, that I need not give any
examples of it.

The law of interrupted or latent transmission by inherit-
ance, which might also be termed alternating transmission,
is in a measure opposed to the preceding law. This im-
portant law appears principally active among many lower
animals and plants, and manifests itself in contrast to the
former in the fact that the offspring are not like their
parents, but very dissimilar, and that only the third or a
later generation becomes similar to the first. The grand-
children are like the grandparents, but quite unlike the
parents. This is a remarkable phenomenon, and, as is well
known, occurs also very frequently, though in a less degree,
in human families. Every one of my readers doubtless
knows some members of a family who, in this or that pecu-
liarity, much more resemble the grandfather or grandmother
than the father or mother. Sometimes it lies in bodily
peculiarities, for example, features of face, colour of hair,
size of body — sometimes in mental qualities, for example,
temperament, energy, understanding — which are trans-
mitted in this manner. This fact may be observed in
domestic animals as well as in the case of man. Among
the domestic animals most liable to vary — as the dog,
horse, and ox — breeders very frequently find that the pro-
duet by breeding resembles the grandparents far more than
it does its own parental organism. If we express this
general law and the succession of generations by the letters
of the alphabet, then A = C = E, whilst B = D = F, and
so on.

LATENT TBANSMISSION. 213

This very remarkable fact appears in a more striking
way in the lower animals and plants than in the higher,
and especially in the well-known phenomenon of alterna-
tion of generations (metagenesis). Here we very frequently
find — for example, among the Planarian worms, sea-squirts
or Tunicates, Zoophytes, and also among ferns and mosses
— that the organic individual in the first place produces, by
propagation, a form completely different from the parental
form, and that only the descendants of this generation,
again, become like the first. This regular change of genera-
tion was discovered by the poet Chamisso, on his voyage
round the world in 1819, among the Salpai, cylindrical tuni-
cates, transparent like glass, which float on the surface of
the sea. Here the larger generation, the individuals of
which live isolated and possess an eye of the form of a
horse-shoe, produce in a non-sexual manner (by the forma-
tion of buds) a completely different and smaller generation.
The individuals of this second smaller generation live united
in chains and possess a cone-shaped eye. Every individual
of such a chain produces, in a sexual manner (hermaphrodite)
again, a non-sexual solitary form of the first and larger
generation. Among the Salpse, therefore, it is always the
first, third, and fifth generations, and in like manner the
second, fourth, and sixth generations, that are entirely like
one another. However, it is not always only one, but in
other cases a number of generations, which are thus leapt
over ; so that the first generation resembles the fourth and
seventh, the second resembles the fifth and eighth, the
third resembles the sixth and ninth, and so on. Three
different generations alternate with one another; for ex-
ample, among the neat little sea-buoys (Doliolum), small

214 THE HISTORY OF CREATION

tunicates closely related to the Salpse. In this case it is
A = D = G, further, B = E = H, and C = F = I. Among
the plant-lice (Aphides), each sexual generation is followed
by a succession of from eight to ten or twelve non-sexual
generations, which are like one another, but differ from
the sexual generations. Then, again, a sexual generation
reappears like the one long before vanished.

If we further follow this remarkable law of latent or in-
terrupted inheritance, and take into consideration all the
phenomena appertaining to it, we may comprise under it
also the well-known phenomena of reversion. By the term
" reversion " or " atavism " we understand the remarkable
fact known to all breeders of animals, that occasionally
single and individual animals assume a fori k which has not
existed for many generations, but belongs to a generation
which has long since disappeared. One of the most remark-
able instances of this kind is the fact that in some horses
there sometimes appear singular dark stripes, similar to
those of the zebra, quagga, and other wild species of
African horses. Domestic horses of the most different races
and of all colours sometimes show such dark stripes ; for ex-
ample, a stripe along the back, a stripe across the shoulders,
and the like. The sudden appearance of these stripes can
only be explained by the supposition that it is the effect of
a latent transmission, a relapse into the ancient original
form, which has long since vanished, and was once common
to all species of horses ; the original form, undoubtedly, was
originally striped like the zebras, quaggas, etc. In like
manner, certain qualities in other domestic animals some-
times appear quite suddenly, which once marked their wild
ancestors, now long since extinct. In plants, also, such

KELOEIA. 215

a relapse can be observed very frequently. All my readers
probably know the wild yellow toad-flax (Linaria vulgaris),
a plant very common in our fields and hedges. Its dragon-
mouthed yellow flower contains two long and two short
stamens. But sometimes there appears a single blossom
(Peloria) which is funnel-shaped, and quite regularly
composed of five individual and equal sections, with five
corresponding stamens. This Peloria can only be ex-
plained as a relapse into the long since extinct and very
ancient common form of all those plants which, like the
toad-flax, possess dragon-mouthed, two-lipped flowers, with
two long and two short stamens. The original form, like
the Peloria, possessed a regular five-spurred blossom,
with five equal stamens, which only later and by degrees
have become unequal. All such relapses are to be
brought under the law of interrupted or latent transmission,
although the number of intervening generations may be
enormous.

When cultivated plants or domestic animals become wild,
when they are withdrawn from the conditions of cultivated
life, they experience changes which appear not only as
adaptations to their new mode of life, but partially also as
relapses into the ancient original form out of which the
cultivated forms have been developed. Thus the different
kinds of cabbage, which are exceedingly different in form,
may be brought back to the original form, by allowing
them to grow wild. In like manner, dogs, horses, heifers,
etc., when growing wild, often revert more or less to a long
extinct generation. An immensely long succession of
generations may pass away before this power of latent
transmission becomes extinguished.

2l6 THE HISTOKY OF CEEATION.

A third law of conservative transmission may be called
the law of sexual transmission, according to which each
sex transmits to the descendants of the same sex pecu-
liarities which are not inherited by the descendants of the
other sex. The so-called secondary sexual characters, which
in many respects are of extraordinary interest, everywhere
furnish numerous examples of this law. Subordinate or
secondary sexual characters are those peculiarities of one
of the two sexes which are not directly connected with the
sexual organs themselves ; characteristics which exclusively
belong to the male sex are, for example, the antlers of the
stag, the mane of the lion, and the spur of the cock. The
human beard, an ornament commonly denied to the female
sex, belongs to the same class. Similar characteristics by
which the female sex is alone distinguished are, for ex-
ample, the developed breasts, with the lactatory glands of
female mammals and the pouch of the female opossum.
The bodily size, also, and complexion, differs in female
animals of many species from that of the male. All these
secondary sexual qualities, like the sexual organs them-
selves, are transmitted by the male organism only to the
male, not to the female, and vice versa. Contrary facts are
rare exceptions to the rule.

A fourth law of transmission, which has here to be men-
tioned, in a certain sense contradicts the last, and limits
it, viz. the law of mixed or mutual (amphigonous) trans-
mission. This law tells us that every organic individual
produced in a sexual way receives qualities from both
parents, from the father as well as from the mother. This
fact, that personal qualities of each of the two sexes are
transmitted to both male and female descendants, is very

WEISMANN'S VIEWS. 2\J

important. Goethe mentions it of himself, in the beautiful
lines —

" Von Vater hab ich die Statur, des Lebens ernstes Fiihren,
Von Miltterchen die Frohnatur and Last zu fabaliren."

" From my father I have my stature and the serious tenor of my life,
From my mother a joyous nature and a turn for poetizing."

This phenomenon is so well known to all, that I need
not here enter upon it. It is according to the different
portions of their character which father and mother
transmit to their children, that the individual differences
among brothers and sisters are chiefly determined. Yet,
as is well known, we very often meet with a cross-inherit-
ance of the two sexes, by the son showing a greater resem-
blance to the mother, whereas the daughter more resembles
the father. This greater resemblance with the parent of
the opposite sex often shows itself very marked, not only
in the outward shape of the body, and especially of the face,
but also in the finer characteristics of the mind, hence of
the molecular formation of the brain.

Extraordinary importance has of late been ascribed to
amphigonous inheritance by Weismann ; he considers it, in
the case of all many-celled organisms (Metazoa and Meta-
phy tse), as the universal cause of their individual variability.
This one-sided idea is connected with the peculiar theory
of the continuity of the germ-plasma, which Weismann
very much over-estimates. As a consequence, he altogether
denies the inheritance of acquired characteristics in general
(see below, p. 221).

The very important and interesting phenomenon of
hybridism also belongs to this law of mixed or amphigonous
transmission It alone, when rightly estimated, is quite

218 THE HISTORY OF CREATION.

sufficient to refute the prevailing dogma of the constancy
of species. Plants, as well as animals, belonging to quite
different species, may sexually mingle with one another
and produce descendants which in many cases can again
propagate themselves, and that indeed either (more fre-
quently) by mingling with one of the two parental species,
or (more rarely) by pure in-breeding, hybrid mixing with
hybrid. The latter is well established, for example, in the
hybrids of hares and rabbits (Lepus Darwinii, p. 151). The
hybrids of a horse and a donkey, two different species of
the same genus (Equus), are well known. These hybrids
differ according as the father or the mother belongs to the
one or the other species — the horse or the donkey. The
mule produced by a mare and a he-donkey has qualities
quite different from those of the jinny (Hinnus), the hybrid
of a horse and a she-donkey. In both cases the hybrid pro-
duced by the crossing of two different species is a mixed
form, which receives qualities from both parents ; but the
qualities of the hybrid are different, according to the form
of the crossing. In like manner, mulattoes produced by
a European and a negress show a different mixture of
characters from the hybrids produced by a negro with a
European female. In these phenomena of hybrid-breeding,
as well as in the other laws of transmission previously
mentioned, we are as yet unable to show the acting causes
in detail ; but no naturalist doubts the fact that the causes
are in all cases purely mechanical and dependent upon the
nature of organic matter itself. If we possessed more
delicate means of investigation than our rude organs of
sense and auxiliary instruments, we should be able to dis-
cover those causes, and to trace them to the chemical and

ONTOGENY AND PHYLOGENY. 219

physical properties of plasmic matter, to their complicate
molecular construction.

Among the phenomena of conservative transmission, we
must now mention, as the fifth law, the law of abridged or
simplified transmission. This law is very important in
regard to embryology or ontogeny, that is, in regard to the
history of the development of organic individuals. Onto-
geny, or the history of the development of individuals, as
I have already mentioned in the first ehapter (p. 10), and
as I shall subsequently explain more minutely, is nothing
but a short and quick repetition of Phylogeny dependent
on the laws of transmission and adaptation — that is, a
repetition of the palaeontological history of development of
the whole organic tribe or phylum, to which the organism
belongs. If, for example, we follow the individual develop-
ment of a man, an ape, or any other higher mammal within
the maternal body from the egg, we find that the foetus or
embryo arising out of the egg passes through a series of
very different forms, which on the whole agrees with, or at
least runs parallel to, a series of forms which is presented
to us by the historical chain of ancestors of the higher
mammals. Among these ancestors we may mention certain
fishes, amphibians, marsupials, etc. But the parallelism or
agreement of these two series of development is never quite
complete ; on the contrary, in ontogeny there are always
gaps and leaps which indicate the omission of certain stages
belonging to the phylogeny. Fritz Muller, in his excellent
work, "Fur Darwin," 16 has clearly shown, in the case of
the Crustacea, or crabs, that "the historical record pre-
served in the individual history of development is gradually
obscured, in proportion as development takes a more and

220 THE HISTORY OF CREATION.

more direct route from the egg to the complete animal."
This process of obscuring and shortening is determined by
the law of abridged transmission, and I mention it here
specially because it is of great importance for the under-
standing of embryology, and because it explains the fact,
at first so strange, that the whole series of forms which our
ancestors have passed through in their gradual development
are no longer visible in the series of forms of our own
individual development from the egg.

Opposed to the laws of the conservative transmission,
hitherto discussed, are the phenomena of the transmission
of the second series, that is, the laws of progressive trans-
mission by inheritance. As already mentioned, they depend
upon the fact that the organism transmits to its descendants
not only those qualities which it has inherited from its own
ancestors, but also a number of those individual qualities
which it has acquired during its own lifetime. Adapta-
tion is here seen to be connected with transmission by
inheritance.

The fundamental importance which the transmission of
acquired qualities possesses for the Theory of Descent, was
clearly recognized as early as the beginning of our century
by Lamarck, and by Darwin's grandfather, Erasmus Darwin.
The new characteristics which originate in the organism
through the influence of the outward conditions of life, as
well as those which arise through its own individual
activity (the use or non-use of organs), may be transmitted
to its descendants, and the original form will thus become
more or less altered. Some recent writers have set too
little value upon this important phenomenon, and Weis-
mann, in fact, completely rejects it. He maintains that

TRANSMISSION OF ACQUIRED CHARACTERS. 221

" we, as yet, do not know of any fact that would actually
prove that acquired characteristics may be transmitted,"
and that "only such characteristics can be transmitted to
a following generation for which a disposition already
existed in the germ." Weismann demands new and con-
vincing proofs for the transmission of adaptations, and in
doing so forgets that such proofs are wholly wanting for
his own, opposite hypothesis ; nay, will probably never be
forthcoming in the sense he desires. In my opinion, as
well as that of many others who hold by transformism, the
direct transmission of new adaptations (in Lamarck's sense)
is a very important fact, and thousands of proofs of this
are furnished by comparative anatomy and ontogeny, by
physiology and pathology. And, indeed, the origin of
thousands of special arrangements remains perfectly un-
intelligible without the supposition ; for instance, functional
and mimetic adaptation, instincts (hereditary psychical
habits), etc. With regard to the inheritance of pathological
changes, the reasons set forth by Virchow, as opposed to
Weismann, are worthy of consideration.

At the head of these important phenomena of progressive
transmission, we may mention the law of adapted or ac-
quired transmission. In reality it asserts nothing more
than what I have said above, that in certain circumstances
the organism is capable of transmitting to its descendants
all the qualities which it has acquired during its own life
by adaptation. This phenomenon, of course, shows itself
most distinctly when the newly acquired peculiarity pro-
duces any considerable change in the inherited form. This
is the case in the examples I mentioned in the preceding
chapter as to transmission in general, in the case of the

222 THE HISTORY OF CREATION.

men with six fingers and toes, the porcupine men, copper
beeches, weeping willows, etc. The transmission of acquired
diseases, such as consumption, madness, and albinism, like-
wise form very striking examples. Albinoes are those
individuals who are distinguished by the absence of colour-
ing matter, or pigments, in the skin. They are of frequent
occurrence among men, animals, and plants. In the case
of animals of a definite dark colour, individuals are not
unfrequently born which are entirely without colour, and
in animals possessing eyes, this absence of pigment extends
even to the eyes, so that the iris of the eye, which is com-
monly of a bright or intense colour, is colourless, but appears
red, on account of the blood-vessels being seen through it.
Among many animals, such as rabbits and mice, albinoes
with white fur and red eyes are so much liked that they
are propagated in great numbers as a special race. This
would be impossible were it not for the law of the trans-
mission of adaptations.

Which of the changes acquired by an organism are trans-
mitted to its descendants, and which are not, cannot be
determined a priori, and we are unfortunately not ac-
quainted with the definite conditions under which the
transmission takes place. We only know in a general way
that certain acquired qualities are much more easily trans-
mitted than others — for example, more easily than the
mutilations caused by accidents. These latter are generally
not transmitted by inheritance, otherwise the descendants
of men who have lost their arms or legs would be born
without the corresponding arm or leg; but here, also,
exceptions occur, and a race of dogs without tails has been
produced by consistently cutting off the tails of both sexes

HORNLESS CATTLE AND OTTEB-SHEEP. 223

of the dog during several generations. A few years ago
a case occurred on an estate near Jena, in which by a
careless slamming of a stable door the tail of a bull was
wrenched off, and the calves begotten by this bull were all
born without a tail. Of late years observations on the
same phenomena in dogs, cats, and mice, which confirm the
above statements, have been communicated by five different
investigators. These are certainly exceptional cases; but
it is very important to note the fact, that under certain
unknown conditions such violent changes are sometimes
transmitted in the same manner as many diseases.

In very many cases the change which is transmitted and
preserved by adapted transmission is constitutional or in-
born, as in the case of albinism mentioned before. The
change then depends upon that form of adaptation which
we call the indirect or potential. A very striking instance
is furnished by the hornless cattle of Paraguay, in South
America. A special race of oxen is there bred which is
entirely without horns. It is descended from a single bull,
which was born in 1770 of an ordinary pair of parents, and
the absence of horns was the result of some unknown cause.
All the descendants of this bull produced with a horned
cow were entirely without horns. This quality was found
advantageous, and by propagating the hornless cattle among
one another, a hornless race was obtained, which at present
has almost entirely supplanted the horned cattle in Paraguay.
The case of the otter-sheep of North America forms a similar
example. In the year 1791 a farmer, by name Seth Wright,
lived in Massachusetts, in North America ; in his normally
formed flock of sheep a lamb was suddenly born with a
surprisingly long body and very short and crooked legs. It

224 THE HISTORY OF CREATION.

was therefore unable to take any great leaps, and especially
unable to leap across a hedge into a neighbour's garden —
a quality which seemed advantageous to the owner, as the
territories were divided by hedges. It therefore occurred
to him to transmit this quality to other sheep, and by
crossing this ram with normally shaped ewes, he produced
a whole race of sheep, all of which had the qualities of the
father, short and crooked legs and a long body. None of
them could leap across the hedges, and they therefore were
much liked and propagated in Massachusetts.

A second law, which likewise belong to the series of pro-
gressive transmissions, may be called the law of established
or habitual transmission. It manifests itself in this, that
qualities acquired by an organism during its individual life
are the more certainly transmitted to its descendants the
longer the causes of that change have been in action, and
that this change becomes the more certainly the property
of all subsequent generations the longer the cause of change
acts upon these latter also. The quality newly acquired
by adaptation or mutation must be established or con-
stituted to a certain degree before we can calculate with
any probability that it will be transmitted at all to the
descendants. In this respect transmission resembles adapta-
tion. The longer a newly acquired quality has been trans-
mitted by inheritance, the more certainly will it be preserved
in future generations. If, therefore, for example, a gardener
by methodical treatment has produced a new kind of apple,
he may calculate with the greater certainty upon preserving
the desired peculiarity of this sort the longer he has trans-
mitted the same by inheritance. The same is clearly shown
in the transmission of diseases. The longer consumption

PERIOD AT WHICH CHARACTERS APPEAR. 225

or madness has been hereditary in a family, the deeper is
the root of the evil, and the more probable it is that all
succeeding generations will suffer from it.

We may conclude the consideration of the phenomena of
inheritance with the two very important laws of homotopio
and contemporaneous transmission by inheritance. We
understand by them the fact that changes acquired by an
organism during its life, and transmitted to its descendants,
appear in the same part of the body in which the parental
organism was first affected by them, and that they also
appear in the offspring at the same age as that at which
they did so in the parent.

The law of contemporaneous or homochronous trans-
mission, which Darwin calls the law of "transmission in
corresponding periods of life," can be shown very clearly in
the transmission of diseases, especially of such as are recog-
nized as very destructive, on account of their hereditary
character. They generally appear in the organism of the
child at the time corresponding with that in which the
parental organism contracted the disease. Hereditary dis-
eases of the lungs, liver, teeth, brain, skin, etc., usually
appear in the descendants at the same period, or a little
earlier than they showed themselves in the parental organ-
ism, or were contracted by it. The calf gets its horns at
the same period of life as its parents did. In like manner
the young stag receives its antlers at the same period of
life in which they appeared in its father or grandfather.
In every one of the different sorts of vine the grapes ripen
at the same time as they did in the case of their progenitors.
It is well known that the time of ripening varies greatly
-in the different sorts; but as all are descended from a

vol. 1. Q

226 THE HISTOKY OP CREATION. -

single species, this variation has heen acquired by the pro-
genitors of the several sorts, and has then been transmitted
by inheritance.

The law of homotopic transmission, which is most closely
connected with the last-mentioned law, and which might
be called the law of transmission in corresponding parts of
the body, may also be very distinctly recognized in patho-
logical cases of inheritance. Large moles, for example, or
accumulations of pigment in several parts of the skin,
tumours also, often appear during many generations, not
only at the same period of life, but also in the same part
of the skin. Excessive development of fat in certain parts
of the body is likewise transmitted by inheritance. Above
all, it is to be noted that numerous examples of this, as well
as of the preceding law, may be found everywhere in the
study of embryology. Both the law of homochronous and
homotopic transmission are fundamental laws of embry-
ology, or ontogeny. For these laws explain the remarkable
fact that the different successive forms of individual develop-
ment in all generations of one and the same species always
appear in the same order of succession, and that the varia-
tions of the body always take place in the same parts.
This apparently simple and self-evident phenomena is
nevertheless exceedingly wonderful and curious ; we cannot
explain its real causes, but may confidently assert that they
are due to the direct transmission of the organic matter
from the parental organism to that of the offspring, as we
have seen above in the case of the .process of transmission
in general, by a consideration of the details of the various
modes of reproduction.

The different laws of conservative and of progressive -trans-

THEORIES OP HEREDITY. 227

mission (which I first elaborated in the nineteenth chapter
of my " General Morphology," and have briefly discussed
here) interact with and through one another in the most
diversified ways, and this accounts for their exceeding
importance for transformations, and, at the same time, for
the great difficulty in penetrating theoretically further into
the nature of these physiological processes. Numerous
endeavours have, indeed, been made since Darwin to set
up molecular hypotheses in order to explain the processes,
but none of these so-called " Theories of Heredity " have
satisfactorily cleared up the obscurity that surrounds them,
or received universal recognition.

If now, in conclusion, we take a glance at these theories
of heredity which have recently been so much discussed,
we must bear in mind that they all possess the value merely
of provisional molecular hypotheses; they cannot be set
up either morphologically by microscopic or anatomical
observation, or physiologically by physical and chemical
demonstration. The plasma or albuminous substance of
the cells, by means of which alone transmission is accom-
plished (both the karyo-plasm of the cell-kernel, as well
as proto-plasm of the cell-body), certainly possesses an ex-
tremely complex and fine molecular structure ; that is, the
smaller and smallest particles of which the plasma consists
are arranged in groups, according to extremely complicate
laws. But unfortunately our microscopic instruments are
much too powerless to enable us to obtain any insight into
this arrangement ; and as little have physics and chemistry
hitherto been able to obtain a satisfactory physiological
idea of the molecular construction and transformation of
the plasma. All the opinions that have been formed of

228 THE HISTORY OF CREATION.

them, and are discussed in the following theories of trans-
mission, are based upon pure conjecture, and are, strictly
speaking, metaphysical speculations. We shall now ex-
amine them in the order in which they appeared : — I. Dar-
win's Theory of Pangenesis (1868) ; II. Haeckel's Theory
of Perigenesis (1876) ; III. Naegeli's Theory of Idioplasm
(1884); IV. Weismann's Theory of Germ-Plasma (1885);
V. Vries' Theory of Intracellular Pangenesis (1889).

I. The Theory of Pangenesis was established by Darwin
in 1868, in his important work on the "Variation of
Animals and Plants under Domestication," and worked out
further in the second edition of this work, published in
1875 (Chap. XXVII.). Darwin assumes that all the cells
of the organism (as living individuals) increase and
differentiate not only by division, but also that they throw
off minute atoms ; these immensely small atoms he calls
gemmules; these gemmmles multiply and aggregate them-
selves into buds and the sexual elements; their develop-
ment depends on their union with other nascent cells or
units, and they are capable of transmission in a dormant
state to successive generations. Besides, every cell can
throw off atoms throughout its entire period of develop-
ment; and these atoms possess, in their dormant state, a
mutual relationship which leads to their aggregation in the
sexual elements.

This provisional hypothesis of Pangenesis, as Darwin
himself cautiously terms it, appears to me the weakest and
most untenable of all the numerous and far-reaching theories
of the great master. I have from the outset considered it
erroneous, and have carefully stated the reasons which
make it impossible for me to accept it, in a work which

THEORY OF PANGENESIS. 229

I shall have to refer to immediately, in connection with
Perigenesis. Darwin's theory seems to me incompatible
with the chief fundamental facts of histology and ontogeny ;
both the construction of the tissues from cells, as well as
the origin of the differentiated cells from germ-layers, and
their development from the fructified egg-cell, appear to
me to stand in irremediable contradiction with the hypothesis
of Pangenesis; consistently carried out, it leads to the
" Pre-formation theory" of Haller and others. The same
may be said also of the modification of this theory which
W. K. Brooks has given in his work on the "Law of
Inheritance" (1883). His Pangenesis does not essentially
differ from Darwin's except for his assumption that the
cells do not continually throw off minute atoms or gemmules,
but only when they find themselves in new and unusual
circumstances. And the male sperm-cell he thinks much
more full of gemmules than the female egg-cell ; hence the
male sperm-cell he thinks represents the more progressive,
the female egg-cell the more conservative element in pro-
pagation and inheritance.

II. The Theory of Perigenesis was established by me in
1876, in a treatise entitled, "On the Wave-production of
Vital Particles, or the Perigenesis of the Plastidules," and
termed a provisional attempt at a mechanical explanation of
the elementary processes of development, more especially of
heriditivity (in No. II. of my " Collected Popular Lectures,"
Bonn, 1879, pp. 25-80). The theory of Perigenesis en-
deavours to explain the nature of inheritance by a simple,
mechanical principle, namely, by the well-known principle
of inherited motion. I assume in every process of repro-
duction that not only the peculiar chemical substance, the

230 THE HISTOEY OF CEEA.TIOST.

plasson or plasma, of the producing organism is transmitted
to the produced organism, but that the special form of the
molecular motion which is connected with its physical,
chemical nature, is also transmitted. In agreement with
our modern histology and histogeny, I assume that the
plasma only (either the karyo-plasm of the cell-kernel or
the cyto-plasm of the cell-substance) is the original bearer
of all the active movements of life, hence also of inheritance
and propagation. This plasma or plasson, in the case of all
plastidules (both the non-kernelled cytods as well as the
genuine kernelled cells), is composed of plastidules or
molecules of plasma ; and these are " probably always sur-
rounded by watery coverings ; the greater or lesser amount
of water — which both separates and connects the neighbour-
ing plastidules — is dependent upon the softer or firmer con-
dition of the plasson " (I.e., p. 8). " Inheritance is the trans-
mission of plastidule motion ; adaptation, on the other hand,
its variation " (p. 55). The movement may be imagined in
the form of the branchings of a wave-movement. In the
case of all Protista, or one-celled organisms (protophyta and
protozoa), this periodical mass-movement proceeds in a com-
paratively simple form, whereas in all Histones, or many-
celled organisms (metaphyta and metazoa), it is connected
with the alternate generation of the plastids and division
of labour of the plastidules. I gave an explanation of this
as early as 1866, in the seventeenth chapter of my " General
Morphology," as Strophogenesis, or series of generations.

The monistic conception of nature may all the more
readily accept my theory of Perigenesis as the basis of a
mechanical theory of inheritance, as I likewise consider the
plastidules as molecules with souls (similar to the " monads "

*THEORY OF IDIOPLASM. 23 r

of Leibnitz), and assume that their movements (attraction
and repulsion) are also connected with sensations (pleasure
and displeasure) like the movements of the atoms of which
they are composed. Without the assumption of some such
lower (unconscious) form of sensation and will-movement
in matter, the simplest chemical and physical processes
remain unintelligible, for surely it is upon this supposition
that the whole idea of elective-relationship or chemical
affinity is based. The plastidules, however, differ from all
other molecules by their capacity for reproduction or for
memory. As Ewald Hering, the physiologist, pointed out,
as early as 1870, in his admirable treatise, " On Memory as
a Universal Function of Organic Matter," unless we assume
some such (unconscious) memory, the most important
phenomena of life, and above all those of propagation
and inheritance, remain utterly unintelligible (p. 51). And
in connection with this he thinks that we may term
" Inheritance the memory of the plastidules, and Variability
their power of apprehension " (p. 72).

III. The Theory of Idioplasm was established in 1884
by Carl Naegeli, in his comprehensive work, " Mechanico-
physiological Theory of the Doctrine of Descent." This
excellent botanist regards idioplasm (i.e. only that portion
of plasma or plasson which, as germ, conveys all the
inheritable qualities, in contrast to the purely nutrition-
plasma) as the essential factor of inheritance and as the
bearer of the transmitted qualities. The minutest particles
of it, which, owing to their peculiar arrangement, deter-
mine the nature of the idioplasm, Naegeli calls Mi-cells;
they correspond in all essential points to my plastidules,
and are conceived, of as surrounded by water. The specific

232 THE HISTOEY OF CREATION.

nature of idioplasm, which is analogous to my plasson, is
said to consist in " the configuration of the cross-section of
strings of parallel rows of mi-cells." The strings of idioplasm
are said to extend through the whole organism in the form
of a large connected (invisible) network This changes
from generation to generation from internal causes, and is
not at all dependent upon the influence'of the external con-
ditions of existence, or is so only to a very small extent.
For the same reason external causes (especially variations
of climate, nutrition, surroundings, etc.) are said not to
exercise any or merely a very unimportant influence upon
the transformation of species. Naegeli assumes rather that
transformation proceeds from an internal, innate principle
of perfecting ; that this effects the transformation of the
smaller or larger groups of forms, in a definite and pro-
gressive direction, and that selection exercises only a very
trifling influence, or none at all.

_ As is evident, Naegeli again introduces a purely teleo-
logical principle into biology for the explanation of in-
heritance and organic development. His "internal principle
of perfecting," which determines the whole development, is
nothing else than the old " vital foree " in a new form ; and
this unknown power is not rendered any the more intel-
ligible to us by the fact that Naegeli sets it up as an
inherent quality of his idioplasm. It is difficult to under-
stand how so clear-sighted a naturalist (who even regards
himself as one of the strictly exact physiologists) could be
so completely deceived as to the true value of his molecular
hypothesis. He rejects both Darwin's Pangenesis and my
Perigenesis, and considers them the "products of nature-
philosophy, and, as such, as good as any other products

THE GERM-PLASMA THEORY. 233

emanating from the same source." In making this state-
ment he fails to see that precisely the same may be said
of his own hypothesis, and that the very same words might
apply to himself — "their fault, as in every other such
philosophical doctrine, is, that they set up their suppositions
as facts, make use of inappropriate scientific designations,
and most unjustifiably assume them to be of scientific
value " (p. 81). The same may be said of the metaphysical
and last part of his work, entitled, " Forces of Forms in the
Domain of Molecules," and more especially of his hypothesis
of isagity (p. 807). No exact physicist could regard it as
anything but a metaphysical speculation full of fancies.
However, apart from his wholly unfounded theory of in-
heritance and many errors connected with it, Naegeli's
work contains a number of valuable contributions to the
theory of descent, but, unfortunately, not its " mechanico-
physiological foundation." Especially excellent are his
chapters on the Phylogenetic History of Development and
Change of Generations (VII. and VIII.), on Morphology
and Classification as Phylogenetic Sciences (IX.), and on
Spontaneous Generation (II.). Many of the details there
given coincide with those which I first developed in my
"General Morphology "in 1866.

IV. Tlie Theory of Germ-plasma was established in 1885
by August Weismann, in a treatise " On the Continuity of
Germ-plasma as the Foundation for a Theory of Inherit-
ance." This theory agrees with the two preceding ones in
assuming that the direct cause of individual development,
and the material basis of inheritance, must be looked for in
the molecules of the plasmic germ-substance, either in the
kernel or in the protoplasm of the propagating cells. But

234 THE HISTOBY OF CREATION.

while my hypothesis of Perigenesis applies the mechanical
principle of transmitted motion to the molecules of plasma
or plastidules, and assumes that their tendency differs
owing to adaptation; and whereas, further, Naegeli, in a
purely teleological manner, imagines some internal, un-
known tendency of perfecting in his idioplasm-molecules
or mi-cells, and assumes these to be connected in strings
forming a network ; — Weismann finds that the actual cause
of inheritance lies in the continuity of the germ-plasma,
and the cause of the variation to lie in the mixing of the
two different germ-plasmas, by sexual propagation. He
assumes that there exist in an organism two completely
distinct species of plasma — the germ-plasma, as the pro-
pagating substance, and the somatic plasma, as the substance
out of which all the tissues of the body become developed
(this distinction was assumed at an earlier date by Rauber,
who speaks of the germinal part and the personal part of
the individual). Weismann further maintains that in every
act of propagation a portion of the parental germ-plasma
is not used for the construction of the filial organism, but
is left behind unchanged, and used for the formation of the
germ-cells for the following generation; that inheritance
depends upon this uninterrupted continuity of the germ-
plasma through a series of generations ; on the other hand,
that adaptation or variation depends upon the individual
difference of the two species of germ-plasmas (of the female
egg-plasma and the male sperm-plasma), which become
mingled in the process of sexual propagation. Weismann
regards it as an important sequence of his theory that an
acquired quality cannot be transmitted. He, therefore,
rejects the most essential principle of the earlier, Lamarckian,

THE GERM-PLASMA THEORY. 235

theory of Descent, and gives the Darwinian principle of
selection the widest scope of activity.

The many morphological and physiological reasons that
contradict Weismann's theory of germ-plasma have already
been brought forward in detail by Virchow, Kblliker,
Detmer, Eimer, Herbert Spencer, and others. And, while
agreeing with them, I wish especially also to point out that
the permanent separation of the two species of plasma in
the germ-cell is not only not proved by microscopic investi-
gation, but is rendered extremely improbable by the facts
of the so-called "cleavage of the egg," and gastrulation.
Besides which, Weismann is thus obliged to assume internal
unknown causes for the development of his germ-plasma,
and these are as metaphysical and teleological as the in-
herent principle of perfecting assumed by Naegeli for his
idioplasm ; the unknown cause differs only in name.
Finally, as Weismann recognizes only the transmissibility
of indirect or potential variations, and altogether rejects
the transmissibility of direct or actual adaptation, he fails,
I think, to give a mechanical explanation of the most
important phenomena of transformation.

V. A Theory of Intracellular Pangenesis (1889) has quite
recently been brought forward by Hugo de Vries, a botanist,
in direct connection with Darwin's hypothesis, but with
this essential difference, that he drops Darwin's supposition
of the transport of the minute germs throughout the body.
Vries assumes this transport as only within every single cell ;
he gives a more careful definition of the minute germs or
gemmules (which he calls Pangens), and assumes that every
single transmissible quality is connected with some such
material bearer, an invisible pangen. The entire living

236 THE HISTORY OP OEEATION.

protoplasm is composed solely of pangens, and in the cell-
kernel are representatives of all species of pangens of the
individual in question.

Vries's treatise is worth reading, admirably written, and
contains instructive ideas on inheritance ; still, like all the
four preceding hypotheses, it fails to give any actual ex-
planation of the molecular processes, nor does it offer any
conceivable idea. The "single transmissible qualities"
again lead back to the pre-formation theory. Further, the
construction and development of animal tissues present
insurmountable difficulties to the acceptance of Vries's
theory, whereas Vries, as a botanist, found no difficulty
with the much simpler and relatively independent vegetable-
cell.

In addition to the above five theories of inheritance,
other naturalists have of late years come forward with
endeavours to explain these wonderful phenomena. How-
ever, they offer either mere unimportant modifications of
one or other of the above-mentioned hypotheses, or they
are so far removed from the thoroughly established basis
of our empiric knowledge, that they need not be taken into
consideration. The question as to whether, in propagation,
merely the kernel of the cells, or the protoplasm, likewise,
is the bearer of the inherited qualities, is now generally
answered in favour of the former. As early as 1866 I had.
maintained, in my " General Morphology," " that the inner
kernel has to attend to the transmission of heritable charac-
teristics, the outer plasma to the adaptation to relations
with the outer world." Of late years, and especially
through the admirable investigations of the brothers Hert-
wig, of E. Strasburger, and others, highly convincing

VALUE OF THE THEOEIES. 237

reasons for the probability of this opinion have been
brought forward.

Our knowledge of inheritance and propagation has made
extraordinary progress during the last thirty years through
the above and numerous other investigations. It is true
none of the five above theories of molecules altogether
explain the enigma of these wonderful processes ; their
merit lies rather in having brought us to a clear conscious-
ness of our inability to comprehend the immensely complex
nature of these invisible processes. However, they have
enabled ns to cast aside the former mystical ideas as to
their nature, and we have arrived generally at the convic-
tion that we have here to deal with physiological functions,
with the vital activity of cell-life, which, like all other
phenomena of life, have to be traced back to chemico-
physical processes; in faet, have to be explained by a
mechanical method.

238 THE HISTORY OF CREATION.

CHAPTER X.

ADAPTATION AND NUTRITION LAWS OF ADAPTATION.

Adaptation and Variation. — Connection between Adaptation and Nutrition
(Change of Matter and Growth). — Distinction between Indirect and
Direct Adaptation. — Laws of Indirect or Potential Adaptation. — Indi-
vidual Adaptation. — Monstrous or Sadden Adaptation. — Sexual Adapta-
tion. — Laws of Direct or Actual Adaptation. — Universal Adaptation. —
Cumulative Adaptation. — Cumulative Influence of External Conditions
of Existence and Cumulative Counter-influence of the Organism. — Free-
will. — Use and Non-Use of Organs. — Practice and Habit. — Functional
Adaptation. — Correlative Adaptation. — Correlation of Development. —
Correlation of Organs. — Explanation of Indirect or Potential Adapta-
tion by the Correlation of the Sexual Organs and of the other Parts
of the Body. — Aping or Mimetic Adaptation (Mimicry). — Divergent
Adaptation. — Unlimited or Infinite Adaptation.

Having now in our two last chapters discussed the most
important laws and theories of inheritance, we now turn to
the second great series of phenomena bearing on natural
selection, viz. to those of adaptation or variation. These
phenomena, taken as a whole, stand in a certain opposition
to the phenomena of inheritance, and the difficulty which
arises in examining these consists mainly in the two sets of
phenomena being so completely intercrossed and inter-
woven. We are but seldom able to say with certainty —
of the variations of form which occur before our eyes — how

INTERACTION OF HEREDITY AND ADAPTATION. 239

much is owing to Inheritance, and how much to Adaptation.
All characters of form, by which organisms are distinguished,
are caused either by Inheritance or by Adaptation ; but as
both functions are continually interacting with each other,
it is extremely difficult for the systematic inquirer to recog-
nize the share belonging to each of the two functions in the
special structure of individual forms. This is, at present,
all the more difficult, because we are as yet scarcely aware
of the immense importance of this fact, and because most
naturalists have neglected the theory of Adaptation, as well
as that of Inheritance. The laws of Inheritance, which we
have just discussed, as well as the laws of Adaptation,
which we shall consider directly, in reality form only a
small portion of the phenomena existing in this domain,
but which have not as yet been investigated ; and since
every one of these laws can interact with every other, it is
clear that there is an infinite complication of physiological
actions, which are at work in the construction of organisms.
But now, as to the phenomenon of variation or adaptation
in general, we must, as in the case of inheritance, view it
as a quite universal, physiological fundamental quality of
all organisms, without exception — as a manifestation of
life which cannot be separated from the idea of an organism.
Strictly speaking, we must here also, as in the case of
inheritance, distinguish between Adaptation itself and
Adaptability. By Adaptation (Adaptio), or Variation
(Variatio), we understand the fact that the organism, in
consequence of influences of the surrounding outer world,
assumes certain new peculiarities in its vital activity, com-
position, and form which it has not inherited from its
parents ; these acquired individual qualities are opposed to

240 THE HISTORY OF CREATION.

those which have been inherited, or, in other words, those
which have been transmitted to it from its parents or
ancestors. On the other hand, we call Adaptability (Adap-
tabilitas), or Variability (Variabilitas), the capability in-
herent in all organisms to acquire such new qualities under
the influence of the outer world.

The undeniable fact of organic adaptation or variation is
universally known, and can be observed at every moment
in thousands of phenomena surrounding us. But just
because the phenomena of variation by external influences
appear so self-evident, they have hitherto undergone scarcely
any accurate scientific investigation. To them belong all
the phenomena which we look upon as the results of con-
tracting and giving up habits, of practice and giving up
practices, or as the results of training, of education, of
acclimatization, of gymnastics, etc Many permanent varia-
tions brought about by causes producing disease, that is to
say, many diseases, are nothing but dangerous adaptations
of the organism to injurious conditions of life. In the case
of cultivated plants and domestic animals, variation is so
striking and powerful that the breeder of animals and the
gardener have founded their whole mode of procedure upon
it, or rather upon the interaction between these phenomena
and those of Inheritance- It is also well known to every
one that animals and plants, in their wild state, are subject
to variation. Every systematic treatise on a group of
animals or plants, if it were to be quite complete and
exhaustive, ought to mention in every individual species
the number of variations which differ more or less from
the prevailing or typical form of the species. Indeed, in
every careful systematic special treatise one finds, in the

ADAPTATION EXPLAINED BY NUTBITION. 24 1

case of most species, mention of a number of such varia-
tions, which are described sometimes as individual devia-
tions, and sometimes as so-called races, varieties, degenerate
species, or subordinate species, and which often differ ex-
ceedingly from the original species, solely in consequence
of the adaptation of the organism to the external conditions
of life.

If we now endeavour to fathom the general causes of these
phenomena of Adaptation, we arrive at the conclusion that
in reality they are as simple as the causes of the phenomena
of Inheritance. We have shown that the nature of the
process of propagation furnishes the real explanation of the
facts of Transmission by Inheritance, that is, the transmis-
sion of parental matter to the body of the offspring ; and
in like manner we can show that the physiological function
of nutrition, or change of substance, affords a general
explanation of Adaptation or Variation. When I here
point to ■" nutrition " as the fundamental cause of variation
and adaptation, I take this word in its widest sense, and
I understand by it all the trophic changes which the
organism undergoes in all its parts through the influences
of the surrounding outer world. Nutrition thus comprises
not only the reception of actual nutritive substances and
the influence of different kinds of food, but also, for example,
the action upon the organism of water and of the atmo-
sphere, the influence of sunlight, of temperature, and of all
those meteorological phenomena which are implied in the
term "climate." The indirect and direct influence of the
nature, of the soil and of the dwelling-place also belong
to it; and further, the extremely important and varied
influence which is exercised upon every animal and every

VOL. I. R

242 THE HISTOEY OF CREATION.

plant by the surrounding organisms, friends and neighbours,
enemies and robbers, parasites, etc. All these and many
other very important influences, all of which more or less
modify the organism in its material composition, must be
taken into consideration in studying the change of sub-
stance which goes on in living things. Adaptation, accord-
ingly, is the consequence of all those material variations
the external conditions of existence produce in the nourish-
ment of the elementary parts, and the influence of the
surrounding outer world produce in the change of substance
and in the growth of the organism.

How very much every organism is dependent upon the
whole of its external surroundings, and changed by their
alteration, is, in a general way, well known to every one.
Only think how much the human power of action is de-
pendent upon the temperature of the air, or how much the
disposition of our minds depends upon the colour of the
sky. Accordingly as the sky is cloudless and sunny, or
covered with large heavy clouds, our state of mind is cheer-
ful or dull. How differently do we feel and think in a
forest during a stormy winter night and during a bright
summer day! All these different modes of our soul depend
upon purely material changes of our brain, upon movements
of molecular plasma, which are started through the medium
of the senses by the different influences of light, warmth,
moisture, etc. "We are a plaything to every pressure of
the air."

No less important and deeply influential are the effects
produced upon our mind and body by the different qiiality
and quantity of food. Our mental activity, the activity of
our understanding and of our imagination, is quite different

NUTRITION EXPLAINS ADAPTATION. 243

accordingly as we have taken tea or coffee, wine or beer,
before or during our work. Our moods, wishes, and feel-
ings are quite different when we are hungry and when we
are satisfied. The national character of Englishmen and of
the Gauchos in South America, who live principally on
meat and food rich in nitrogen, is wholly different from
that of the Irish, feeding on potatoes, and that of the
Chinese, living on rice, both of whom take food deficient
in nitrogen. The latter also form much more fat than the
former. Here, as everywhere, the variations of the mind
go hand in hand with the corresponding transformations of
the body; both are produced by purely material causes.
But all other organisms, in the same way as man, are varied
and changed by the different influences of nutrition. It is
well known that we can change in an arbitrary way the
form, size, colour, etc., of our cultivated plants and domestic
animals, by change of food ; that, for example, we can take
from or give to a plant definite qualities, accordingly as we
expose it to a greater or less degree of sunlight and moisture.
As these phenomena are generally widely known, and as
we shall proceed presently to the consideration of the
different laws of adaptation, we will not dwell here any
longer on the general facts of variation.

As the different laws of transmission may be naturally
divided into the two series of conservative and progressive
transmission, so we may also distinguish between two series
of the laws of adaptation, first, the series of laws of indirect,
and secondly, the series of laws of direct adaptation. The
latter may also be called the laws of actual, and the former
the laws of potential adaptation.

The first series, comprising the phenomena of indirect

244 TH E HISTORY OF CREATION. '

(potential) adaptation, has, on the whole, hitherto been
little attended to, and Darwin has the merit of having
directed special attention to this series of changes. Of late
years August Weismann has investigated them very care-
fully, and places such exclusive importance in them as the
sole transmissible deviations, that he finally altogether
rejects the inheritance of direct adaptations. It is some-
what difficult to place this subject clearly before the reader ;
I will endeavour to make it clear hereafter by examples.
Speaking quite generally, indirect or potential adaptation
consists in the fact that certain changes in the organism,
effected by the influence of nutrition (in its widest sense)
and of the external conditions of existence in general, show
themselves not in the individual form of the respective
organism, but in that of its descendants. Thus, especially
in organisms propagating themselves in a sexual way, the
reproductive system, or sexual apparatus, is often influenced
by external causes (which little affect the rest of the
organism) to such a degree that its descendants show a
complete alteration of form. This can be seen very
strikingly in artificially produced monstrosities. Mon-
strosities can be produced by subjecting the parental
organism to certain extraordinary conditions of life, and,
curiously enough, such an extraordinary condition of life
does not produce a change of the organism itself, but a
change in its descendants. This cannot be called trans-
mission by inheritance, because it is not a quality existing
in the parental organism that is transmitted by inheritance.
It is, on the contrary, a change affecting the parental
organism, but not perceptible in it, that appears in the
peculiar formation of its descendants. It is only the

DIRECT AND INDIRECT ADAPTATION. 245

impulse to this new formation which is transmitted in
propagation through the egg of the mother or the sperm
of the father. The new formation exists in the parental
organism only as a possibility (potential) ; in the descendants
it becomes a reality (actual).

As this very important and very general phenomenon had
hitherto been entirely neglected, people were inclined to
consider all the visible variations and transformations of
organic forms as phenomena of adaptation of the second
series, that is, as phenomena of direct or actual adaptation.
The nature of this latter kind of adaptation consists in the
fact that the change affects the organism itself (through
nutrition, etc.), and shows itself immediately by some trans-
formation, and does not only make itself apparent in the
descendants. To this class belong all the well-known
phenomena in which we can directly trace the transforming
influence of climate, food, education, training, etc., in their
effects upon the individual itself.

We have seen how the two series of phenomena of pro-
gressive and conservative transmission, in spite of their
difference in principle, in many ways interfere with and
modify each other, and in many ways co-operate with and
cross each other. The same is the case, in a still higher
degree, in the two series of phenomena of indirect and
direct adaptation, which are opposed to each other and yet
closely connected. Some naturalists, especially Darwin,
Carl Vogt, and Weismann, ascribe to the indirect or potential
adaptation by far the more important and almost exclusive
influence. But the majority of naturalists have hitherto
been inclined to take the opposite view, and to attribute the
principal influence to direct or actual adaptation. I con-

246 THE HISTORY OF CREATION,

sider this controversy, in the "mean while, as almost useless.
It is but seldom that we are in a condition, in any individual
case of variation, to judge how much of it belongs to direct
and how much to indirect adaptation. We are, on the
whole, still too little acquainted with these exceedingly
important and intricate relations, and can only assert, in a
general way, that the transformation of organic forms is to
be ascribed either to direct adaptation alone, or to indirect
adaptation alone, or lastly, to the co-operation of both direct
and indirect adaptation. The physiology of nutrition will
have to solve the important problem, to investigate the
different effects of these changes (experimentally if possible)
and to trace them back to their elementary causes, to the
physico-chemical processes in the change of substance, and
in the growth of the organs.

Let us now turn our attention somewhat more closely to
the different forms of variation, which we may meanwhile
term the " laws of adaptation." We shall in the first place
examine the variations of the first series, indirect or
potential adaptation. Although the nature of these re-
markable phenomena is still very obscure, and their primary
causes have been but little investigated, one fact remains
universally recognized and unquestioned, that organic indi-
viduals experience transformations and assume new forms
in consequence of changes of nutrition not experienced by
themselves, but by the parental organism. The transform-
ing influence of the external conditions of existence, of
climate, of nutrition, etc., shows its effects here not directly
in the transformation of the organism itself, but indirectly
in that of its descendants.

The principal and most universal of the laws of indirect

LAW OF INDIVIDUAL ADAPTATION. 247

variation may be termed the law of individual adaptation,
or the important proposition that all organic individuals
from the commencement of their individual existence are
unequal, although often very much alike. As a proof of
this proposition, I may at once point to the fact, that in
the human race in general all brothers and sisters, all
children of the same parents, are unequal from their birth.
No one will venture to assert that two children at their
birth are perfectly alike : that the size of the individual parts
of their bodies, the number of hairs on their heads, the
number of cells composing their outer skins or epidermis, or
that the number of blood-cells are the same in both children,
or that both children have come into the world with the
same abilities or talents. But what more specially proves
this law of individual indifference, is the fact that in the
case of those animals which produce several young ones at
a time — for instance, dogs and cats— all the young of each
birth differ from one another more or less strikingly in
size and colour of the individual parts of the body, or in
strength, etc. Now, this law is universal. All organic indi-
viduals from their beginning are distinguished by certain,
though often extremely minute differences, and the cause
of these individual differences, though in detail usually
utterly unknown to us, depends partly or entirely on certain
influences which the organs of propagation in the parental
organism have undergone. Many naturalists consider indi-
vidual variation as the most important, or even as the
exclusive cause of the transformation; thus, for instance,
August Weismann, who regards it as the direct consequence
of sexual propagation, Amphigonous Transmission, accord-
ing to him, directly affects the individual adaptation. But

248 THE HISTORY OF CREATION.

however high we may estimate its value, we cannot admit
its exclusive importance.

A second law of indirect adaptation, which we shall call
the law of monstrous or sudden adaptation, is of less
importance and less general than the law of individual
adaptation. Here the divergences of the child-organism
from the parental form are so striking that, as a rule, we
may designate them as monstrosities. In many cases they
are produced, as has been proved by experiments, by the
parental organism having been subject to a certain treat-
ment, and placed under peculiar conditions of nutrition ;
for example, when air and light are withdrawn from it, or
when other influences powerfully acting upon its nutrition
are changed in a certain way. The new condition of exist-
ence causes a strong and striking modification of form, not
directly of the organism itself, but only of that of its de-
scendants. The mode of this influence in detail we cannot
discover, and we can only in a very general way detect a
casual connection between the abnormal formation of the
child and a certain change in the conditions of existence
of its parents exerting a special influence upon the organs
of propagation in the latter. The previously mentioned
phenomenon of albinism probably belongs to this group of
abnormal or sudden variations, also the individual cases of
human beings with six fingers and toes, the case of the
hornless cattle, as well as those of sheep and goats with
four or six horns. The abnormal deviation in all these
cases probably owes its origin to a cause which at first only
affected the reproductive system of the parental organism,
the egg of the mother or the sperm of the father.

A third curious manifestation of indirect adaptation may

INDIRECT ADAPTATION. 249

be termed the law of sexual adaptation. Under this name
we indicate the remarkable fact that certain influences,
which act upon the male organs of propagation only, affect
the structure of the male descendants, and in like manner
other influences, which act upon the female organs of pro-
pagation only, manifest their effect only in the change
of structure of the female descendants. This remarkable
phenomenon is still very obscure, and has not as yet been
investigated, but is probably of great importance in regard
to the origin of " secondary sexual characteristics," to which
we have already made allusion.

All the phenomena of sexual, monstrous, and individual
adaptation, which we may comprise under the name of the
laws of indirect or potential adaptation, are as yet very
little known to us in their real nature and in their deeper
casual connection. Only this much we can at present main-
tain with certainty, that numerous and important trans-
formations in organic forms owe their existence to this
process. Many and striking variations of form solely depend
on causes which at first only affect the nutrition of the
parental organism, and thereupon its organs of propagation.
Evidently the relations in which the sexual organs stand to
other parts of the body are of the greatest importance. We
shall have more to say of these presently, when we speak
of the law of correlative adaptation. How powerfully the
variations in the conditions of life and nutrition affect the
propagation of organisms is rendered obvious by the re-
markable fact that numerous wild animals which we keep
in our zoological gardens, and exotic plants which are grown
in our botanical gardens, are no longer able to reproduce
themselves. This is the case, for example, with most birds

250 THE HISTORY OF CREATION.

of prey, parrots, and monkeys. The elephant, also, and the
animals of prey of the bear genus, in captivity hardly ever
produce young ones. In like manner many plants in a
cultivated state become sterile. The two sexes may indeed
unite, but no fructification, or no development of the fructi-
fied germ, takes place. From this it follows with certainty
that the changed mode of nutrition in the cultivated state
is able completely to destroy the capability of reproduction,
and therefore to exercise the greatest influence upon the
sexual organs. In like manner other adaptations or varia-
tions of nutrition in the parental organism may cause, not
indeed a complete want of descendants, but still important
changes in their form.

Much better known than the phenomena of indirect or
potential adaptation are those of direct or actual adapta-
tion, to the consideration of which we now turn our atten-
tion. To them belong all those changes of organisms which
are generally considered to be the results of practice, habit,
training, education, etc. ; also those changes of organic
forms which are effected directly by the influence of nutri-
tion, of climate, and other external conditions of existence.
As has already been remarked in direct or actual adaptation,
the transforming influence of the external cause affects the
form of the organism itself, and does not only manifest
itself in that of the descendants.

We may place the law of universal adaptation at the
head of the different laws of direct or actual adaptation,
because it is the chief and most comprehensive among them.
It may be briefly explained in the following proposition :
" All organic individuals become unequal to one another in
the course, of .their life by adaptation to different conditions

INDIBECT ADAPTATION, 251

of life, although the individuals of one and the same species
remain mostly very much alike." A certain inequality of
organic individuals, as we have seen, had already to be
assumed in virtue of the law of individual (indirect) adapta-
tion. But, beyond this, the original inequality of individuals
is afterwards increased by the fact that every individual,
during its own independent life, subjects and adapts itself
to its own peculiar conditions of existence. All different
individuals of every species, however like they may be in
their first stages of life, become in the further course of
their existence less like to one another. They deviate
from one another in more or less important peculiarities,
and this is a natural consequence of the different conditions
under which the individuals live. There are no two single
individuals of any species which can complete their life
under exactly the same external circumstances. The vital
conditions of nutrition, of moisture, air, light ; further, the
vital conditions of society, the inter-relations with sur-
rounding individuals of the same or other species, are
different in every individual being; and this difference first
affects the functions, and later changes the form of every
individual organism. If the children of a human family
show, even at the beginning, certain individual inequalities
which we may consider as the consequence of individual
(indirect) adaptation, they will appear still more different
at a later period of life, when each child has passed through
different experiences, and has adapted itself to different
conditions of life. The original difference of the individual
processes of development evidently becomes greater the
longer the life lasts and the more various the external con-
ditions which influence the separate individuals. This may

252 THE HISTORY OF" CREATION.

be demonstrated in the simplest manner in man, as well as
in domestic animals and cultivated plants, in which the
vital conditions may be arbitrarily modified. Two brothers t
of whom one is brought up as a workman and the other as
a priest, develop quite differently in body as well as in
mind ; in like manner, two dogs of one and the same birth,
of which one is trained as a sporting dog and the other
chained up as a watch-dog. The same observation may
also readily be made as to organic individuals in a natural
state. If, for instance, one carefully compares all the trees
in a fir or beech forest, which consists of trees of a single
species, one finds that, among all the hundreds or thousands
of trees, there are not two individual trees completely agree-
ing in size of trunk and other parts, in the number of
branches, leaves, etc. Everywhere we find individual in-
equalities which, in part at least, are merely the conse-
quences of the different conditions of life under which the
trees have developed. It is true we can never say with
certainty how much of this dissimilarity in all the indi-
viduals of every species may have originally been caused by
indirect individual adaptation, and how much of it acquired
under the influence of direct or universal adaptation.

A second series of phenomena of direct adaptation, which
we may comprise under the law of cumulative adaptation,
is no less important and general than universal adaptation.
Under this name I include a great number of very important
phenomena, which are usually divided into two quite
distinct groups. Naturalists, as a rule, have distinguished,
first, those variations of organisms which are produced
directly by the permanent influence of external con-
ditions (by the constant action of nutrition, of climate, of

DIBECT ADAPTATION. 253

surroundings, etc.), and secondly, those variations which
arise indirectly from habit and practice, from accustoming
themselves to definite conditions of life, and from the use
and non-use of organs. The latter influences have been set
forth especially by Lamarck as important causes of the
change of organic forms, "while the former have for a very
long time been recognized as such more generally.

The sharp distinction usually made between these two
groups of cumulative adaptation, and which even Darwin
maintained, disappears as soon as we reflect more accurately
and deeply upon the real nature and causal foundation of
these two, apparently very different, series of adaptations.
We then arrive at the conviction that in both cases there
are always two different active causes to be dealt with : on
the one hand, the external influence or action of adaptative
conditions of life, and on the other hand, the internal re-
action of the organism which subjects and adapts itself to
that condition of life. If cumulative adaptation is con-
sidered from the first point of view alone, and the transform-
ing influences of the permanent external conditions of life
are traced to those conditions solely, then the principal
stress is laid unduly upon the external factor, and the
necessary internal reaction of the organism is not taken into
proper consideration. If, on the other hand, cumulative
adaptation is regarded solely in relation to its second factor,
and the transforming action of the organism itself, its
reaction against the external influences, its change by
practice, habit, use, or non-use of organs, is put into the
foreground, then we forget that this reaction is first called
into play by the action of external conditions of existence.
Hence it seems that the distinction made between these two

254 THE HISTORY OF CREATION.

groups lies only in the different manner of viewing them,
and I believe that they can, with full justice, he considered
as one. The most essential fact in these phenomena of
cumulative adaptation is that the change of the organism
which manifests itself first in the functions, and at a later
period in the form, is the result either of long enduring,
or of often repeated, influences of an external cause. The
smallest cause, by cumulation of its action, can attain the
greatest results.

There are innumerable examples of this kind of direct
adaptation. In whatever direction we may examine the
life of animals and plants, we discover on all hands
evident and undeniable changes of this kind. Let me first
mention some of those phenomena of adaptation occasioned
directly by nutrition itself. Every one knows that the
domestic animals which are bred for certain purposes can
be variously modified, according to the different quantity
and quality of the food given to them. If a farmer in
breeding sheep wishes to produce fine wool, he gives them
different food from what he would give if he wished to
obtain good flesh or an abundance of fat. Choice race and
carriage horses receive better food than dray and cart
horses. Even the bodily form of man — for example, the
amount of fat — is quite different according to his nutrition.
Food containing much nitrogen produces little fat, that
containing little nitrogen produces a great deal of fat.
People who, by means of Banting's system, lately so
popular, wish to become thin eat only meat and eggs — no
bread, no potatoes. The important variations that can be
produced among cultivated plants, solely by changing the
quantity and quality of nourishment, are well known. The

DIRECT ADAPTATION, 255

same plant acquires an altogether different appearance,
according as it is placed in a dry and warm place, exposed
to the sunlight or placed in a cool damp spot in the shade.
Many plants, if transferred to the sea-shore, get, in a short
space of time, thick, fleshy leaves, and the same plants
placed in a particularly dry and hot locality get thin hairy
leaves. All these variations arise directly from the cumu-
lative influence of changed nutrition.

But it is not only the quantity and quality of the means
of nutrition which affect and powerfully change and trans-
form the organism, but it is affected also by all the other
external conditions of existence, above all by its nearest
organic surroundings, the society of friendly or hostile
organisms. One and the same kind of tree develops quite
differently in an open locality, where it is free on all sides,
to what it does in a forest, where it must adapt itself to
its surroundings, where it is pressed on all sides by its
nearest neighbours, and is forced to shoot upwards. In
the former case, the branches of the tree spread widely out ;
in the latter, the trunk extends upwards, and the top of
the tree remains small and contracted. How powerfully
all these circumstances, and how powerfully the hostile or
friendly influence of surrounding organisms, of parasites,
etc., affect every animal and every plant, is so well known,
that it appears superfluous to quote further examples. The
change of form, or transformation which is thereby effected,
is never solely the direct result of the external influence,
but must always be traced to the corresponding reaction,
and to the activity of the organism itself, which consists in
contracting a habit, or practice, and in the use or non-use
of organs. The fact that these latter phenomena, as a rule,

256 THE HISTOEY OF CKEATI0N7

have been considered distinct from the former, is owing first
to the one-sided manner of viewing them already mentioned,
and secondly to the wrong notion which has been formed
as to the nature and the influence of the activity of the
will in animals.

The activity of the will, which is the origin of habit, of
practice, of the use or non-use of organs among animals, is,
like every other activity of the animal soul, dependent
upon material processes in the central nervous system,
upon peculiar motions which emanate from the albuminous
matter of the ganglion cells, and the nervous fibres con-
nected with them. The will, as well as the other mental
activities, in higher animals, in this respect is different from
that of men only in quantity, not in quality. The will of
the animal, as well as that of man, is never free. The
widely spread dogma of the freedom of the will is, from
a scientific point of view, altogether untenable. Every
physiologist who scientifically investigates the activity of
the will in man and animals, must of necessity arrive at the
conviction that in reality the will is never free, but is
always determined by external or internal influences. These
influences are for the most part ideas which have been
either formed by Adaptation or by Inheritance, and are
traceable to one or other of these two physiological functions.
As soon as we strictly examine the action of our own will,
without the traditional prejudice about its freedom, we
perceive that every apparently free action of the will is
the result of previous ideas, which are based on notions
inherited or otherwise acquired, and are therefore, in the
end, dependent on the laws of Adaptation and Inheritance.
The- same also applies to the action of the will in all animals.

DISUSE OF ORGANS. 257

As soon as their will is considered in connection with their
mode of life, in its relation to the changes which the mode
of life is subject to from external conditions, we are at once
convinced that no other view is possible. Hence the
changes of the will which follow the changes of nutrition,
and which, in the form of practice, habit, etc., produce
variations in structure, must be reckoned among the other
material processes of cumulative adaptation.

Whilst an animal's will is adapting itself to changed
conditions of existence by the acquisition of new habits,
practices, etc., it not unfrequently effects the most remark-
able transformations of the organic form. Numerous
instances of this may be found everywhere in animal life.
Thus, for example, many organs in domestic animals are
suppressed, when in consequence of a changed mode of life
they cease to act. Ducks and fowls in a wild state fly
exceedingly well, but lose this facility more or less in a
cultivated state. They accustom themselves to use their
legs more than their wings, and in consequence the muscles
and parts of the skeleton used in flying are essentially
changed in their development and form. Darwin has
proved this by a very careful comparative measurement
and weighing of the respective parts of the skeleton in the
different races of domestic ducks, which are all descended
from the wild duck (Anas boschas). The bones of the
wings in tame ducks are weaker, the bones of the legs, on
the other hand, are more strongly developed than in wild
ducks. In ostriches and other running birds which have
become completely unaccustomed to fly, the consequence is
that their wings are entirely crippled and have degenerated
into mere "rudimentary organs." In many domestic

vol. 1. s

258 THE HISTORY OF CREATION.

animals, especially in many races of dogs and- rabbits,
we find that in the cultivated state they have acquired
pendulous ears. This is simply a consequence of a
diminished use of the auricular muscles. In a wild state
these animals have to exert their ears very much in order
to discover an approaching foe, and this is accompanied by
a strong development of the muscular apparatus which
keeps the outer ears in an upright position, and by which
they can turn them in all directions. In a domestic state
the same animals no longer require to listen so attentively,
they prick up or turn their ears only a little ; the auricular
muscles cease to be used, gradually become weakened, and
the ears hang down flabbily, or become rudimentary.

As in these cases the function, and consequently the form
also, of the organ becomes degenerated through disuse, so,
on the other hand, it becomes more developed by greater
use. This is particularly striking if we compare the brain,
and the mental activity belonging to it, in wild animals
and those domestic animals which are descended from
them. The dog and horse, which are so vastly improved
by cultivation, show an extraordinary degree of mental
development in comparison with their wild original
ancestors, and evidently the change in the bulk of the
brain, which is connected with it, is mainly determined by
persistent exercise. It is also well known how quickly
and powerfully muscles grow and change their form by
continual practice. Compare, for example, the arms and
legs of a trained gymnast with those of an immovable
bookworm.

1 How powerfully external influences affect the habits of
animals and their mode of life, and in this way still further

THE : GILLS OF SALAMANDEBS. 259

change their forms, is very strikingly shown in many cases
among amphibious animals and reptiles. Our commonest
indigenous snake, the ringed snake, lays eggs which require
three weeks' time to develop. But when it is kept in
captivity, and no sand is strewn in the cage, it does not lay
its eggs, but retains them until the young ones are developed.
The difference between animals producing living offspring
and those laying eggs is here effaced simply by the change
of the ground upon which the animal lives.

The water-salamanders, or tritons, which have been
artificially made to retain their original gills, are extremely
interesting in this respect. The tritons are amphibious
animals, nearly akin to frogs, and possess, like the latter,
in their youth external organs of respiration — gills — with
which they, while living in water, breathe the air dissolved
in the water. At a later date a metamorphosis takes place
in tritons, as in frogs. They leave the water, lose their
gills, and accustom themselves to breathe with their lungs.
But if they are prevented from doing this by being kept
shut up in a tank, they do not lose their gills. The gills
remain, and the water-salamander continues through life
in that low stage of development, beyond which its lower
relations, the gilled salamanders, or Sozobranchiata, never
pass. The gilled salamander attains its full size, its sexual
development, and reproduces itself without losing its gills.

Great interest was caused a short time ago, among
zoologists, by the axolotl (Siredon pisciformis), a gilled
salamander from Mexico, nearly related to the triton; it
had already been known for a long time, and been bred on
a large scale in the zoological garden in Paris. This animal
possesses external gills, like the young salamander, but

2<5o THE HISTORY OF CREATION.

retains them all its life, like all other Sozobranehiata. This
gilled salamander generally remains in the water, with its
aquatic organs of respiration, and also propagates itself
there. But in the Paris garden, unexpectedly from among
hundreds of these animals, a small number crept out of
the water on to the dry land, lost their gills, and changed
themselves into gill-less salamanders, which cannot be
distinguished from a North-American genus of tritons
(Amblystoma), and breathe only through lungs. In this
exceedingly curious case we can directly follow the great
stride from water-breathing to air-breathing animals, a
stride which can indeed be observed every spring in the
individual history of development of frogs and salamanders.
Just as every separate frog and every separate salamander
transforms itself from an amphibious animal breathing
through gills, at a later period into one breathing through
lungs, so the whole group of frogs and»salamanders have
arisen from animals breathing through gills, and akin to
the Siredon. The Sozobranehiata have remained up to the
present day in that low stage of development. Ontogeny
here explains phylogeny ; the history of the development
of individuals explains that of the whole group (p. 10).

The important variations of organizations which have
recently been very thoroughly and clearly explained by
Wilhelm Roux as Functional Adaptations stand in direct
connection with the phenomena of Cumulative Adaptation,
and partly under the same idea. Roux's treatise on " The
Struggle of the Parts of Organisms " (1881) is one of the
most important of the recent contributions to our Darwinian
literature. In agreement with Lamarck, Roux starts with
the morphological actions of the physiological functions or

TRANSMISSION OF ACQUIRED VARIATIONS. 26 1

life-activities. He points out to what a great extent they
are strengthened by the use of the organs, and weakened
by their non-use; the former brings about Hypertrophy
and the growth of the organs, the latter Atrophy and
degeneration of the organs. He very justly lays great
stress upon the undoubted transmission of such acquired
variations, and emphasizes the differentiating and con-
structive effect of the functional stimuli. Specially im-
portant, however, are his explanations of the far-reaching
and direct variations, which affect the increased or lessened
use of the organs in the tissues of which they are composed,
and in the cells of which the tissues are built up. In my
" General Morphology " I had, in 1866, already pointed to
these significant variations in my endeavours to trace back
all adaptations to nutrition as their physiological funda-
mental bases (vol. ii. p. 193). Roux enters more fully into
the subject, and explains the trophic action of the functional
stimulus as the actively and passively working parts. He
points out in the case of the finer structure of the bones
and muscles, of the glands and blood-vessels, that their
extremely suitable arrangement may have proceeded directly
from the trophic influence of functional stimulus. From
this it is clear how the utmost conceivable perfecting of the
organization can be accomplished directly by means of the
vital activity of organisms themselves, as a teleological
piece of mechanism, which has no conscious object or so-
called plan of structure. But it at the same time shows
how the new suitable arrangements ma}' be directly trans-
mitted by inheritance, without there being any necessary
or special selection.

In close connection with the two preceding series of

262 THE HISTORY OF CREATION.

phenomena, Cumulative and Functional Adaptation, we
have the law of Correlative Adaptation. According to this
important law, actual adaptation not only changes those
parts of the organism which are directly affected by its
influence, but other parts also not directly affected by it.
This is the consequence of organic solidarity, and especially
of the unity of the nutrition existing among all the parts of
every organism. If, for example, the hairiness of the leaves
increases in a plant by its being transferred to a dry locality,
then this change reacts upon the nutrition of other parts,
and it may result in a shortening of the parts of the stalk,
and produce a more contracted form of the whole plant.
In some races of pigs and dogs — for example, in the Turkish
dog — which by adaptation to a warmer climate have more
or less lost their hair, the teeth also have degenerated.
Whales and Edentata (armadillos), which by their curious
skin-covering are removed from the other mammals, also
show the greatest deviations in the formation of their teeth.
Further, those races of domestic animals (oxen and pigs)
which have acquired short legs have, as a rule, also a short
and compact head. Among other examples, the races of
pigeons which have the longest legs are also characterized
by the longest beaks. The same correlation between the
length of the legs and beaks is universal in the order of
stilted-birds (Grallatores), in storks, cranes, snipe, etc. The
correlations which thus exist between different parts of the
organism are most remarkable, but their real cause is un-
known to us. In general, we can of course say, the changes
of nutrition affecting an individual part must necessarily
react on the other parts, because the nutrition of every
organism is a connected, centralized activity, But why

CORRELATION OF ORGANS. 263

just this or that part should exhibit this or that particular
correlation is in most cases quite unknown to us. W©
know a great number of such correlations in formation;
they are especially seen in those changes of animals and
plants which give rise to an absence of pigment (noticed
previously) — in albinoes. The want of the usual colouring
matter goes hand in hand with certain changes in the
formation of other parts; for example, of the muscular and
osseous systems, consequently of organic systems which are
not at all ultimately connected with the system of the
outer skin. Very frequently albinoes are more feebly
developed, and consequently the whole structure of the
body is more delicate and weak than in coloured animals
of the same species. The organs of the senses and nervous
system are in like manner curiously affected when there is
this want of pigment. White cats with blue eyes are nearly
always deaf. White horses are distinguished from coloured
horses by their special liability to form sarcomatous tumours.
In man, also, the degree of the development of pigment in
the outer skin greatly influences the susceptibility of the
organism for certain diseases ; so that, for instance, Europeans
with a dark complexion, black hair, and brown eyes become
more easily acclimatized to tropical countries, and are less
subject to the diseases there prevalent (inflammation of the
liver, yellow fever, etc.) than Europeans of white complexion,
fair hair, and blue eyes.

Among these correlations in the formation of different
organs, those are specially remarkable which exist between
the sexual organs and other parts of the body. No change
of any part reacts so powerfully upon the other parts of
the body a,s a. certain treatment of the sexual organs.

264 THE HISTOBY OF CREATION.

Farmers who wish to obtain an abundant formation of fat
in pigs, sheep, etc., remove the sexual organs by cutting
them out (castration), and this is indeed done to animals of
both sexes. The result is an excessive development of fat*
The same is done to the singers in certain religious corpora-
tions. These unfortunates are castrated in early youth, in.
order that they may retain their high boyish voices. In
consequence of this mutilation of the genitals, the larynx
remains in its youthful stage of development. The
muscular tissues of the body remain at the same time
weakly developed, while below the skin an abundance of
fat accumulates. But this mutilation also powerfully
reacts upon the development of the nervous system, the
energy of the will, etc., and it is well known that human
castrates, or eunuchs, as well as castrated animals, are
utterly deficient in the special psychical character -.which
distinguishes the male sex. Man is a man, both in body
and soul, solely through his male generative glands.

These most important and influential correlations between
the sexual organs and the other parts of the body, especially
the brain, are found equally in both sexes. This might be
expected even d, priori, because in most animals the two
kinds of organs develop themselves from the same founda-
tion, and at the beginning are not different. In man, as
in the rest of the vertebrate animals, the male and female
organs in the original state of the germ are entirely the
same, and the differences of the two sexes only gradually
arise in the course of embryonic development (in man, in
the ninth week of embryonic life, see Plates II. and III.);
by one and the same gland developing in the female as the
ovary, and in the male as the testicle. Every change of

CORRELATIONS OF THE SEXUAL GLANDS. 265

the female ovary, therefore, has a no less important reaction
upon the whole female organism than every change of the
testicle has upon the male organism. Virchow has expressed
the importance of this correlation in his admirable essay on
" Das Weib und die Zelle " (" Woman and the Cell "), in the
following words : " Woman is woman only by her sexual
glands ; all the peculiarities of her body and mind, of her
nutrition and her nervous activity, the sweet delicacy and
roundness of her limbs, the peculiar formation of the pelvis,
the development of the breasts, the continuance of the high
voice, that beautiful ornament of hair on her head, with
the scarcely perceptible soft down on the rest of the skin —
then, again, the depth of feeling, the truth of her direct per-
ceptions, her gentleness, devotion, and fidelity — in short, all
the feminine qualities which we admire and honour in a
true woman are but a dependence of the ovary. Take this
ovary away, and the man-woman stands before us — a
loathly abortion."

The same close correlation between the sexual organs and
the other parts of the body occurs among plants as generally
as among animals. If one wishes to obtain an abundance
of fruit from a garden plant, the growth of the leaves is
curtailed by cutting off some of them. If, on the other
hand, an ornamental plant with a luxuriance of large and
beautiful leaves is desired, then the development of the
blossoms and fruit is prevented by cutting off the flower-
buds. In both cases one system of organs develops at the
cost of the others. Thus, also, most variations in the forma-
tion of leaves in wild plants result in corresponding trans-
formations of the generative parts or blossoms. The great,
importance of this " compensation of development," of this

266 THE HISTORY OF CREATION.

'f correlation of parts," had been already set forth by Goethe,
by Geoffrey St. Hilaire, and other nature-philosophers. It
rests mainly upon the fact that direct or actual adaptation
cannot produce an important change in a single part of the
body, without at the same time affecting the whole organism.

The correlative adaptation between the reproductive
organs and the other parts of the body deserves a very
special consideration, because it is, above all others, likely
to throw light upon the obscure and mysterious phenomena
of indirect or potential adaptation, which have already
been considered For just as every change of the sexual
organs powerfully reacts upon the rest of the body, so on
the other hand every important change in another part of
the body must necessaily more or less react on the sexual
organs. This reaction, however, will only become per-
ceptible in the formation of the offspring which arise out
of the changed generative parts. It is, in fact, precisely
those remarkable and imperceptible changes of the genital
system (in themselves utterly insignificant changes) —
changes of the eggs and the sperm — brought about by such
correlations, which have the greatest influence upon the
formation of the offspring, and all the phenomena of indirect
or potential adaptation previously mentioned may in the
end be traced to correlative adaptation.

A further series of remarkable examples of correlative
adaptation is furnished by the different animals and plants
which become degenerated through parasitic life or para-
sitism. No other change in the mode of life so much
affects the shapes of organisms as the adoption of a
parasitical life. Plants thereby lose their green leaves;
as, for instance, our native parasitical plants, Orobanche,

MIMETIC ADAPTATION. 267

Lathrsea, Monotropa. Animals which originally have lived
freely and independently, but afterwards adopt a parasitical
mode of life on other animals or plants, in the first place
cease to use their organs of motion and their organs of
sense. The loss of this activity is succeeded by the loss of
the organs themselves, and thus we find, for example, many
crabs, or Crustacea, which in their youth possess a tolerably
high degree of organization, viz. legs, antennae, and eyes, in
old age completely degenerate, living as parasites, without
eyes, without apparatus of motion, and without antennae.
The lively, active form of youth has become a shapeless,
motionless lump. Only the most necessary organs of nutri-
tion and propagation retain their activity ; all the rest of
the body has degenerated. Evidently these complete trans-
formations are, to a large extent, the direct consequences of
cumulative adaptation, of the non-use and defective exercise
of the organs, but a great portion of them must certainly
be attributed also to correlative adaptation. (Compare
Plates X. and XI.)

A specially interesting series of variations which are in
many ways connected with the preceding laws of direct
Adaptation, is formed by Mimetic Adaptation, " Mimicry."
It is met with among land-animals, more especially in
insects, and among water-animals in the crabs. In these
two classes of animals there are numerous species which so
closely resemble other species of entirely different families
that they are apt to be confounded with them. We may
specially mention as examples of mimetic adaptation those
insects (e.g. butterflies or their caterpillars) which are
avoided or feared by other insects owing to peculiarly bad
habits ; for instance, owing to the unsavoury taste of their

268 THE HISTOEY OP OBBATION.

flesh, their bad smell, their being armed with stings, thorns,
and other such weapons. Butterflies and caterpillars of
several perfectly distinct families have, by Mimetic Adapta-
tion, acquired the same form, colour, and tracings belonging
to other families which are avoided owing to their smell
or the taste of their flesh, or on account of their terrifying
appearance, or their armour. Among insects bees and
wasps are especially feared owing to their poisonous sting.
Hence there are insects, of not less than five or six wholly
distinct orders, which have gradually, by natural selection,
become strangely like wasps: the butterflies (Sesia), the
scarabee (Odontorera), further numerous Diptera (flies
and gnats), various grasshoppers (Orthoptera), hemipters
(Hemiptera), and others. Their terrifying resemblance to
wasps is of the greatest use to all of these insects, inasmuch
as it protects them from their numerous enemies and per-
secutors. There are also numerous innocent snakes which
have gradually become extremely like certain poisonous
snakes, having " mimicked " them in form, colour, and
tracings; thus, for instance, our innocent ringed-snake
(Coronella Icevis) has copied the poisonous viper (Vipera
berus). As protective resemblance is in many other cases
also (for instance, in the selection of similar colours) the
cause of striking transformations, it may likewise be classed
among the series of Mimetic Adaptations.

Another law of adaptation is the law of divergent adapta-
tion. By this law we indicate the fact that parts originally
formed alike have developed in different ways under the
influence of external conditions. This law of adaptation is
extremely important for the explanation of the phenomenon
of division of labour, or polymorphism. We can see this

DIVERGENT ADAPTATION. 269

very easily in our own selves ; for instance, in the activity
of our two hands. We usually accustom our right hand to
quite different work from that which we give our left, and
in consequence of the different occupation there arises a
different formation of the two hands. The right hand,
which we use much more than the left, shows a stronger
development of the nerves, muscles, and bones. The same
applies to the whole arm. In most human beings the
bones and flesh of the right arm are, in consequence of
their being more employed, stronger and heavier than
those of the left arm. Now, as the special use of the right
arm has been adopted and transmitted by inheritance for
thousands of years among most races of men, the stronger
shape and size of the right arm have already become
hereditary. P. Harting, an excellent Dutch naturalist, has
shown, by measuring and weighing newly born children,
that even in them the right arm is more developed than
the left.

According to the same law of divergent adaptation, both
eyes also frequently develop differently. If, for example,
a naturalist accustoms himself always to use one eye for
the microscope (it is better to use the left), then that eye
will acquire a power different from that of the other, and
this division of labour is of great advantage. The one eye
will become more short-sighted, and better suited for seeing
things near at hand; the other eye becomes, on the con-
trary, more long-sighted, more acute for looking at an
object in the distance. If, on the other hand, the naturalist
alternately uses both eyes for the microscope, he will not
acquire the short-sightedness of the one eye and the com-
pensatory degree of long-sight in the other, which is attained

2>0 THE HISTORY OF CREATION.

by a wise distribution of these different functions of sight
between the two eyes. Here then again the function, that
is the activity, of originally equally formed organs can
become divergent by habit; however, the function reacts
again upon the form of the organ, and upon the internal
structure.

. Divergent adaptation can very easily be perceived among
plants, especially in creepers. Branches of one and the
same creeping plant, which originally were formed alike,
acquire a completely different form and extent, a com-
pletely different degree of curvature and diameter of spiral
winding, according as they twine themselves round a
thinner or a thicker bar. The divergent change of form
of parts originally identical in form — which tending in
different directions develop themselves under different
external conditions — can be distinctly demonstrated in
many other examples. As this divergent adaptation inter-
acts with progressive inheritance, it becomes the cause of
a division of labour among the different organs.

An eighth and last law of adaptation we may call the
law of unlimited or infinite adaptation. By it we simply
mean to express that we know of no limit to the variation
of organic forms occasioned by the external conditions of
existence. We can assert of no single part of an organism,
that it is no longer variable, or that if it were subjected to
new external conditions it would not be changed by them.
It has never yet been proved by experience that there is a
limit to variation. If, for example, an organ degenerates
from non-use, this degeneration ends finally in a complete
disappearance of the organ, as is the case with the eyes of
many animals. On the other hand, we are able, by continual

adaftatIOh is unlimited. 271

-practice, habit, and the ever-increasing use of ah organ, to
bring it to a degree of perfection which we should at the
beginning have considered to be impossible. If we compare
the uncivilized savages with civilized nations, we find
among the former a development of the organs of sense —
sight, smell, and hearing — such as civilized nations can
hardly conceive of. On the other hand, the brain, that is,
mental activity, among more civilized nations is developed
to a degree of which the wild savages have no idea.

There appears indeed to be a limit given to the adapt-
ability of every organism, by the "type" of its tribe or
phylum ; that is, by the essential fundamental qualities
of this tribe, which have been inherited from a common
ancestor, and transmitted by conservative inheritance to all
its descendants. Thus, for example, no vertebrate animal
can acquire the ventral nerve-chord of articulate animals,
instead of the characteristic spinal marrow of the vertebrate
animals. However, within this hereditary primary form,
within this inalienable type, the degree of adaptability is
unlimited. The elasticity and fluidity of the organic form
manifests itself, within the type, freely in all directions,
and to an unlimited extent. But there are some animals,
as, for example, the parasitically degenerate crabs and
worms, which seem to pass even the limit of type, and have
forfeited all the essential characteristics of their tribe by an
astonishing degree of degeneration.

As to the adaptability of man, it is, as in all other
animals, also unlimited, and since it is manifested in him
above all other animals, in the modifications of the brain,
there can be absolutely no limit to the knowledge which
man in a further progress of mental cultivation may not be

272 THE HISTORY OF CREATION.

able to attain to. Even the human mind, according to the
law of unlimited adaptation, enjoys an infinite perspective
of becoming ever more and more perfect. It is this con-
sideration which proves the worthlessness of the much-
talked-of " Ignorabimus Speech," which Du Bois Reymond,
the Berlin physiologist, in 1873, most unjustifiably directed
against the advance of science in his discourse "On the
Limits to our Knowledge of Nature" ("TJber die Grenzen
des Naturkennens "). I have entered my protest against
this infamous " Ignorabimus Speech " — which clerical
obscurantism has made its watchword — in the preface to
my " Anthropogeny " (1874), and again in my treatise
on "Freedom in Science and Teaching" ("Freie Wissen-
schaft und freie Lehre ").

These remarks are sufficient to show the extent of the
phenomena of Adaptation, and the great importance to be
attached to them. The laws of Adaptation, or the facts of
Variation, are just as important as the laws of Inheritance.
All phenomena of Adaptation can, in the end, be traced to
conditions of nutrition of the organism, in the same way as
the phenomena of Inheritance are referable to conditions of
reproduction ; but the latter, as well as the former, may
further be traced to chemical and physical, that is, to
mechanical causes. According to Darwin's Theory of
Selection, the new forms of Organisms, the transformations
which artificial selection produces in the state of cultivation,
and which natural selection produces in the state of nature,
arise solely by the interaction of such causes.

( 273 )

CHAPTER XI

NATURAL SELECTION BY THE STRUGGLE FOR EXIST-
ENCE. CELLULAR SELECTION AND PERSONAL
SELECTION.

Interaction of the Two Organic Formative Causes, Inheritance and Adapta-
tion. — Natural and Artificial Selection. — Struggle for Existence, or
Competition for the Necessaries of Life. — Disproportion between the
Number of Possible or Potential, and the Number of Eeal or Actual
Individuals. — Complicated Correlations of all Neighbouring Organisms.
— Mode of Action in Natural Selection. — Homochromic Selection as
the Cause of Sympathetic Colourings. — Sexual Selection as the Cause.
of the Secondary Sexual Characters. — The Struggle of Parts in the
Organism (Roux). — Functional* Self- Formation of Suitable Structures.
— Teleological Mechanism. — Cellular Selection (Protista) and Persona
Selection (Histonee). — Selection of the Cells and of the Tissues. —
The Principle of Selection in Empedocles. — Mechanical Origin of what
is Suitable for a Purpose from what is Unsuitable. — Philosophical
Range of Darwinism.

In order to arrive at a right understanding of Darwinism,
it is, above all, necessary that the two organic functions
of Inheritance and Adaptation, which we examined in
our last chapters, should be more closely examined. If we
do not, on the one hand, examine the purely mechanical
nature of these two physiological activities, and the various
action of their different laws, and if, on the other hand, we
do not consider how complicated the interaction of these
VOL I. T

274 THB HISTOET OF CREATION.

different laws of Inheritance and Adaptation must be, we
shall not be able to understand how these two functions, by
themselves, have been able to produce all the variety of
animal and vegetable forms, which, in fact, they have. We
have, at least, hitherto been unable to discover any other
formative causes besides these two, and if we rightly under-
stand the necessary and infinitely complicated interaction
of Inheritance and Adaptation, we do not require to look
for other unknown causes for the change of organic forms.
These two fundamental causes are, as far as we can see,
completely sufficient.

Even long before Darwin had published his Theory of
Selection, some naturalists, and especially Goethe, had as-
sumed the interaction of two distinct formative tendencies
— a conservative or preserving, and a progressive or
changing formative tendency — as the causes of the variety
of organic forms. The former was called by Goethe the
centripetal or specifying tendency, the latter the centrifugal
tendency, or the tendency to metamorphosis. These two
tendencies completely correspond with the two processes
of Inheritance and Adaptation. Inheritance is the centri-
petal or internal formative tendency which strives to keep
the organic form in its species, to form the descendants like
the parents, and always to produce identical things from
generation to generation. Adaptation, on the other hand,
which counteracts inheritance, is the centrifugal or external
formative tendency, which constantly strives to change the
organic forms through the influence of the varying agencies
of the outer world, to create new forms out of those existing,
and entirely to destroy the constancy or permanency of
species. Accordingly as Inheritance or Adaptation pre-

ADAPTATION VERSUS INHERITANCE. 275

dominates in the struggle, the specific form either remains
constant or changes into a new species. The degree of con-
stancy of form in the different species of animals and plants,
which obtains at any moment, is simply the necessary
result of the momentary predominance which either of
these two formative powers (or physiological activities) has
acquired over the other.

If we now return to the consideration of the process of
selection or choice, the outlines of which we have already
examined, we shall be in a position to see clearly and dis-
tinctly that both artificial and natural selection rest solely
upon the interaction of these two formative tendencies. If
we carefully watch the proceedings of an artificial selector —
a farmer or a gardener — we find that only these two con-
structive forces are used by him for the production of new
forms. The whole art of artificial selection rests solely upon
a thoughtful and wise application of the laws of Inheritance
and Adaptation, and upon their being applied and regulated
in a skilful and systematic manner. Here the will of man
constitutes the selecting force.

The case of natural selection is quite similar, for it also
employs merely these two organic constructive forces, the
physiological functions of Adaptation and Heredity, in
order to produce the different species. But the selecting
principle or force, which in artificial selection is represented
by the conscious will of man acting for a definite purpose,
consists in natural selection of the unconscious struggle for
existence acting without a definite plan. What we mean
by " struggle for existence " has already been explained in
the seventh chapter. It is the recognition of its exceeding
importance which constitutes one of the greatest of Darwin's

276 THE HISTORY OF CREATION.

merits. But as this relation is very frequently imperfectly
or falsely understood, it is necessary to examine it now
more closely, and to illustrate by a few examples the
operation of the struggle for life, and the part it plays in
natural selection.

When considering the struggle for life, we started from
the fact that the number of germs which all animals and
plants produce is infinitely greater than the number of
individuals which actually come to life and remain alive
for a longer or shorter time. Most organisms produce
during life thousands or millions of germs, from each of
which, under favourable circumstances, a new individual
might arise. In most animals and plants these germs are
eggs, that is cells, which for their development require
sexual fructification. But many of the Protista, those one-
celled, lowest organisms, which are neither animals nor
plants, propagate themselves only in a non-sexual manner ;
the germ-cells, or spores, require no fructification. Now, in
all cases the number of unsexual, as well as of sexual germs,
is out of all proportion to the number of actually living
individuals of every species.

Taken as a whole, the number of living animals and
plants on our earth remains always about the same. The
number of places in the economy of nature is limited, and
in most parts of the earth's surface these places are always
approximately occupied. Certainly there occur everywhere
and in every year fluctuations in the absolute and in the
relative number of individuals of all species. However,
taken as a whole, these fluctuations are of little importance,
and it is a fact that the total number of all individuals
remains, on an average, almost constant. There is a con-

INCREASE COMPARATIVELY SLOW. 277

stant fluctuation from year to year occasioned by one or
other series of animals and plants predominating, and that
every year the struggle for life somewhat alters their
relations.

Every single species of animal and plant would have
densely peopled the whole earth's surface in a short time,
if it had not had to struggle against a number of enemies
and hostile influences. Even Linnaeus calculated that if an
annual plant only produced two seeds (and there is not one
which produces so few), it would have yielded in twenty
years a million of individuals. Darwin has calculated of
elephants, which of all animals seem the slowest to increase,
that in five hundred years the descendants of a single pair
would amount to fifteen millions of individuals ; this is
supposing that every elephant, during its period of fertility
(from the 30th to the 90th year), produced only three pairs
of young ones, and survived itself to its hundredth year.
In like manner the increase of the number of human beings
— if calculated on the average proportion of births to popu-
lation, and no hindrances to the natural increase stood in
the way — would be such as to double the total in twenty-
five years. In every century their total number would
have increased sixteen-fold ; whereas we know that the
total number of human beings increases but slowly, and
that the increase of population is very different in different
countries. While European tribes spread over the whole
globe, other tribes or species of men every year draw nearer
to their complete extinction. This is the case especially
with the redskins of America, and with the copper-coloured
natives of Australia. Even if these races were to propagate
more abundantly than the white Europeans, yet they would

278 THE HISTORY OF CREATION, ;

sooner or later succumb to the latter in the struggle for life.
But of all human individuals, as of all other organisms, by
far the majority perish at the earliest period of their lives.
Of the immense quantity of germs which every species
produce, only very few actually succeed in developing, and
of these few it is again only a very small portion which
attain to the age in which they can reproduce themselves. ;
From the disproportion between the immense excess of
organic germs and the small number of chosen individuals
which are actually able to continue in existence beside one
another, there follows of necessity that universal struggle
for life, that constant fight for existence, that perpetual
competition for the necessaries of life, of which I gave a
sketch in my seventh chapter. It is this struggle for life
which brings natural selection into play, which in its turn
is made use of by the interaction of Inheritance and Adap-
tation as a sifting agency, and which thus causes a con 7
tinual change in all organic forms. In this struggle for
acquiring the necessary conditions of existence, those indi-
viduals will always overpower their rivals who possess any
individual privilege, any advantageous quality, of which
their fellow-competitors are destitute. It is true we are
able only in the fewest cases (in those animals and plants
best known to us) to form an approximate conception of
the infinitely complicated interaction of the numerous cir^
cumstances, all of which here come into combination. Only
think how infinitely varied and complicated are the rela-
tions of every single human being to the rest of mankind,
and in fact to the whole of the surrounding outer world.
But similar relations prevail also among all animals and
plants which live together in one plape. All influence one

COMPLICATED CORRELATIONS. 279

another actively or passively. Every animal and every
plant struggles directly with a number of enemies, beasts
of prey, parasitic animals, etc. Plants standing together
struggle with one another for the space of ground requisite
for their roots, for the necessary amount of light, air,
moisture, etc. In like manner, animals living together
struggle with one another for their food, dwelling-place,
etc. In this most active and complicated struggle, any
personal superiority, however small, any individual advan-
tage, may possibly decide the issue in favour of the one
possessing it. This privileged individual remains the victor
in the struggle, and propagates itself, while its fellow-com-
petitors perish before they succeed in propagating them-
selves. The personal advantage which gave it the victory
is transmitted by inheritance to its descendants, and by a
further development may become so strongly marked as
to cause us to consider the later generations as a new
species.

The infinitely complicated correlations which exist be-
tween the organisms of every district, and which must be
looked upon as the real conditions of the struggle for life,
are mostly unknown to us, and are very difficult to dis-
cover. We have hitherto been able to trace them only to
a certain point in individual cases, as in the example given
by Darwin of the relations between cats and red clover in
England. The red clover (Trifolium pratense), which in
England is among the best fodder for cattle, requires the
visit of humming-bees in order to attain the formation of
seeds. These insects, while sucking the honey from the
bottom of the flower, bring the pollen in contact with the
stigma, and thus cause the fructification of the flower,

28o THE HISTOKY OP CREATION.

which never takes place without it. Darwin has shown
by experiments, that red clover which is not visited by
humming-bees does not yield a single seed. The number
of bees is determined by the number of their enemies, the
most destructive of which are the field-mice. The more
the field-mice predominate, the less the clover is fructified.
The number of field-mice, again, is dependent upon the
number of their enemies, principally cats. Hence in the
neighbourhood of villages and towns, where many cats are
kept, there are plenty of bees. A great number of cats,
therefore, is evidently of great advantage for the fructifica-
tion of clover. This example may be followed still further,
as has been done by Carl Vogt, if we consider that cattle
which feed on red clover are one of the most important
foundations of the wealth of England. Englishmen preserve
their bodily and mental powers chiefly by making excellent
meat — roast beef and beefsteak — their principal food. The
English owe the superiority of their brains and minds over
those of other nations in a great measure to their excellent
meat. But this is clearly indirectly dependent upon the
cats, which pursue the mice. We may, with Huxley, even
trace the chain of causes to those old maids who cherish
and keep cats, and, consequently, are of the greatest impor-
tance to the fructification of the clover and to the prosperity
of England. From this example we can see that the further
it is traced the wider is the circle of action and of correla-
tion. We can with certainty maintain that there exist a
great number of such correlations in every plant and in
every animal, only we are not always able to point out and
survey their concatenation as in the last instance.

Another remarkable example of important correlations is

IMPORTANT COKEELATIONS. 281

the following, given by Darwin. In Paraguay, there are
no wild oxen and horses, as in the neighbouring parts of
South America, both north and south of Paraguay. This
surprising circumstance is explained simply by the fact
that in that country a kind of small fly is very frequent,
and is in the habit of laying its eggs in the navel of newly
born calves and foals. The newly born animals die in con-
sequence of this attack, and the small deadly fly is therefore
the cause of oxen and horses never becoming wild in that
district. Supposing that this fly were destroyed by some
insect-eating bird, then these large mammals would grow
wild in Paraguay, as well as in the neighbouring parts of
South America ; and as they would eat a quantity of
certain species of plants, the whole flora, and, consequently
again, the whole fauna of the country would become
changed. It is hardly necessary to state, that at the same
time the whole economy, and consequently the character,
of the human population would alter. It is much the same
with the Tse-tse fly in Africa.

Thus the prosperity, nay, even the existence of whole
populations can be indirectly determined by a single small
animal or vegetable form in itself extremely insignificant.
There are small coral islands whose human inhabitants live
almost entirely upon the fruit of a species of palm. The
fructification of this palm is principally effected by insects,
which carry the pollen from the male to the female palm
trees. The existence of these useful insects is endangered
by insect-eating birds, which in their turn are pursued by
birds of prey. The birds of prey, however, often succumb
to the attack of a small parasitical mite, which develops
itself in millions in their feathers. This small, dangerous

282 THE HISTOEY OF CREATION.

parasite, again, may be killed by parasitical moulds.
Moulds, birds of prey, and insects would in this case favour
the prosperity of the palm, and consequently of man ; birds,
mites, and insect-eating birds would, on the other hand,
endanger it.

Interesting examples in relation to the change of correla-
tions in the struggle for life are furnished also by those
isolated oceanic islands, uninhabited by man, on which at
different times goats and pigs have been placed by navi-
gators. These animals become wild, and having no enemies,
they increase in number so excessively, that the rest of the
animal and vegetable population suffer in consequence, and
the island finally may become almost a waste, because there
is insufficient food for the large mammals which increase
too numerously. In some cases on an island thus overrun
with goats and pigs, other navigators have let loose a
couple of dogs, who enjoyed this superabundance of food,
and they again increased so numerously, and made such
havoc among the herds, that after several years the dogs
themselves lacked food, and they also almost died out.
The equilibrium of species continually changes in this
manner in nature's economy, accordingly as one or another
species increases at the expense of the rest. In most cases
the relations of different species of animals and plants to
one another are much too complicated for us to be able to
follow them, and I leave it to the reader to picture to
himself what an infinitely complicated machinery is at work
in every part of the world in consequence of this struggle.
The impulses which started the struggle, and which altered
and modified it in different places, are in the end seen to be
the impulses of self-preservation — in fact, the instinct lead-

THE EQUILIBRIUM OP SPECIES. 283

ing individuals to preserve themselves (the instinct of
obtaining food), and the instinct leading them to preserve
the species (instinct of propagation). It is these two funda-
mental instincts of organic self-preservation of which
Schiller, the idealist (not Goethe, the realist !), says —

" Meanwhile, until philosophy
Sustains the structure of the world,
Her workings will be carried on
By hunger and by lore." *

It is these two powerful fundamental instincts which, by
their varying activity, produce such extraordinary differ-
ences in species through the struggle for life. They are the
foundations of the phenomena of Inheritance and Adapta-
tion. We might, in fact, trace all phenomena of Inheritance
to propagation, all phenomena of Adaptation to nutrition,
as the material, fundamental cause.

The struggle for life in natural selection acts with as
much selective power as does the will of man in artificial
selection. The latter, however, acts according to a plan
and consciously, the former without a plan and uncon-
sciously. This important difference between artificial and
natural selection deserves especial consideration. For we
learn by it to understand how arrangements serving a
purpose can be produced by mechanical causes acting without
an object, as well as by causes acting for an object. The
products of natural selection are arranged even more for
a purpose than the artificial products of man, and yet they
owe their existence not to a creative power acting for a

* " Einstweilen bis den Ban der Welt
Philosophic zusammenhalt,
Erhalt sich ihr Getriebe
Durch Hunger und durch Liebe."

284 THE HISTORY OF CREATION.

definite purpose, but to a mechanical relation acting un-
consciously and without a plan. If we had not thoroughly
considered the interaction of Inheritance and Adaptation
under the influence of the struggle for life, we should not
at first be inclined to expect such results from this natural
process of selection as are, in fact, furnished by it. It may
therefore be appropriate here to mention a few especially
striking examples of the activity of natural selection.

Let us first take Darwin's homochromic selection of
animals, or the so-called " sympathetic selection of colours,"
into consideration. Earlier naturalists have remarked that
numerous animals are of nearly the same colour as their
dwelling-place, or the surroundings in which they per-
manently live. Thus, for example, plant-lice and many
other insects living on leaves are of a green colour. The
inhabitants of the deserts, the jerboa or leaping mice, foxes
of the desert, gazelles, lions, etc., are mostly of a yellow or
yellowish- brown colour, like the sand of the desert. The
polar animals, which live on the ice and snow, are white
or grey, like ice and snow. Many of these animals change
their colour in summer and winter. In summer, when the
snow partly vanishes, the fur of these polar creatures
becomes brownish-grey or blackish, like the naked earth,
while in winter it again becomes white. Butterflies and
insects which hover round the gay and bright flowers are
like them in colour. Now, Darwin explains this surprising
circumstance quite simply by the fact that such colours as
agree with the colour of the habitation are of the greatest
use to the animals concerned. If these animals are animals
of prey, they will be able to approach the object of their
pursuit more safely and with less likelihood of observation,

PKOTECTIVE COLOURING. 285

and, in like manner, those animals which are pursued will
be able to escape more easily, if their colour is as little
different as possible from that of their surroundings. If
therefore originally an animal species varied so as to present
cases of all colours, those individuals whose colour most
resembled the surroundings must have been most favoured
in the struggle for life. They remained more unobserved,
maintained and propagated themselves, while those indi-
viduals or varieties differently coloured died out.

I have tried to explain, by the same sympathetic selec-
tion of colour, the wonderful fact that the majority of
pelagic glass-like animals — that is, of those which live on
the surface of the open sea — are bluish, or completely colour-
less and transparent, like glass and water itself. Such
colourless, glassy animals are met with in the most different
classes. To them belong, among fish, the Helmicthyidse,
through whose crystalline bodies the words of a book can
be read ; among the molluscs, the finned snails (Heteropods)
and butterfly snails (Pteropods) ; among worms, the Alciope
and Sagitta ; among Tunicates, the Salpse or Sea-barrels ;
further, a great number of pelagic crabs (Crustacea), and
the greater part of the Medusae; Umbrella-jellies (Discome-
dusse) ; Comb-jellies (Ctenophora). All of these pelagic
animals, which float on the surface of the ocean, are trans-
parent and colourless, like glass and like the water itself,
while their nearest kin live at the bottom of the ocean, and
are coloured and opaque like the inhabitants of the land.
This remarkable fact, like the sympathetic colouring of the
inhabitants of the earth, can be explained by natural
selection. Among the ancestors of the pelagic glass-like
animals which showed a different degree of colourlessness

286 THJE HISTORY OF CREATION

and transparency, those that were the most colourless and
transparent must have heen most favoured in the active
struggle for life which takes place on the surface of the
ocean. They were enabled to approach their prey the most
easily unobserved, and were themselves least observed by
their enemies. Hence they could preserve and propagate
themselves more easily than their more coloured and opaque
relatives ; and finally, by accumulative adaptation and
transmission by inheritance, by natural selection throughout
the course of many generations, their bodies would attain
that degree of crystal-like transparency and colourlessness
which we at present admire in them.

No less interesting and instructive than homochromic
selection is that species of natural selection which Darwin
calls "sexual selection," and it explains the origin of the
so-called " secondary sexual characters." We have already
mentioned these subordinate sexual characteristics, so in-
structive in many respects. They comprise those pecu-
liarities of animals and plants which belong only to one
of the two sexes, and which do not stand in any direct
relation to the act of propagation itself.

Such secondary sexual characters occur in great variety
among the higher classes of animals. We all know how
striking is the difference of the two sexes in size and
colour in many birds and butterflies. The male sex is
generally the larger and more beautiful. It often possesses
special decorations or weapons; as, for example, the spur
and comb of the cock, the antlers of the stag and deer, etc.
All these peculiarities of the two sexes have nothing
directly to do with propagation itself, which is effected by
the " primary sexual characters," or actual sexual organs.

SECONDARY SEXUAL CHARACTERS. 287

Now, the origin of these remarkable "secondary sexual
characters " is explained by Darwin simply by a choice or
selection which takes place in the propagation of animals.
In most animals the number of individuals of both sexes is
unequal; either the number of the female or the number
ofvthe male individuals is greater, and, as a rule, when
the season of propagation approaches, a struggle takes
place between the rivals for the possession of the animals
of the other sex. It is well known with what vigour and
vehemence this struggle is fought out among the higher
animals — among mammals and birds — especially among those
of polygamous habits. Among gallinaceous birds, where for
one cock there are several hens, a severe struggle takes place
between the competing cocks for as large a harem as possible.
The same is the case with many ruminating animals.
Among stags and deer, for instance, at the period of rut,
deadly struggles take place between the males for the
possession of the females. The secondary sexual character
which here distinguishes the males — the antlers of stags
and deer — not possessed by the female, is, according to
Darwin, the consequence of that struggle. Here the motive
and cause determining the struggle is not, as in the case of
the struggle for individual existence, self-preservation, but
the preservation of the species — propagation. There are
numerous passive weapons of defence, as well as active
weapons for attack. The lion's mane, not possessed by the
female, is evidently such a weapon of defence ; it is an
excellent means of protection against the bites which the
male lions try to inflict on each other's necks when fighting
for the females ; consequently those males with the strongest
manes have the greatest advantage in the sexual struggle.

288 THE HISTORY OP CREATION.

The dewlap of the ox and the comb of the cock are similar
defensive weapons. Active weapons of attack, on the other
hand, are the antlers of the stag, the tusks of the boar, the
spur of the cock, and the hugely developed pair of jaws in
the male stag-beetle ; all are instruments employed by the
males in the struggle for the females, for annihilating or
chasing away their rivals.

In the cases just mentioned, it is the bodily "struggle to
the death " which determines the origin of the secondary
sexual characters. But, besides these mortal struggles, there
are other important competitions in sexual selection, which
no less influence the structure of the rivals. These consist
principally in the fact that the courting sex tries to please
the other by external finery, by beauty of form, or by a
melodious voice. Darwin thinks that the beautiful voices
of singing birds have principally originated in this way.
Many male birds carry on a regular musical contest - when
they contend for the possession of the females. It is known
of several singing birds, that in the breeding season the
males assemble in numbers round the females, and let their
songs resound before them, and that then the females choose
the singers who best please them, for their mates. Among
other songsters, individual males pour out their songs in the
loneliness of the forest in order to attract the females, and
the latter follow the most attractive calls. A similar musical
contest, though certainly less melodious, takes place among
crickets and grasshoppers. The male cricket has on its belly
two instruments like drums, and produces with these the
sharp chirping notes which the ancient Greeks curiously
enough thought beautiful music. Male grasshoppers, partly
by using their hind-legs like the bow of a violin against

SEXUAL SELECTION. 289

their wing-coverings, and partly by rubbing their wing-
coverings together, bring out tones which are, indeed, not
melodious to us, but which please the female grasshoppers
so much that they choose the male who fiddles the best.

Among other insects and birds it is not song or, in fact,
any musical accomplishment, but finery or beauty of the
one sex which attracts the other. Thus we find that, among
most gallinaceous birds, the cocks are distinguished by eombs
on their heads, or by a beautiful tail, which they can spread
out like a fan ; as, for example, in the case of the peacock
and turkey-cock. The magnificent tail of the bird of para-
dise is also an exclusive ornament of the male sex. In like
manner, among very many other birds and very many
insects, principally among butterflies, the males are dis-
tinguished from the females by special colours or other
decorations. These are evidently the results of sexual
selection. As the females do not possess these attractions
and decorations, we must come to the conclusion that they
have been acquired by degrees by the males in the competi-
tion for the females, which takes its origin in the selective
discrimination of the females.

We may easily picture to ourselves, in detail, the appli-
cation of this interesting conclusion to the human com
munity. Here, also, the same causes have evidently in-
fluenced the development of the secondary sexual characters.
The characteristics distinguishing the man, as well as those
distinguishing the woman, owe their origin, certainly for the
most part, to the sexual selection of the other sex. In an-
tiquity and in the Middle Ages, especially in the romantic
age of chivalry, it was the bodily struggles to the death — the
tournaments and duels — which determined the choice of the

vol. 1. u

290 THE HISTORY OP CREATION.

bride ; the strongest carried home the bride. In more recent
times, however, in our so-called " polished " or " highly civil-
ized " society, competing rivals prefer to contend indirectly
by means of musical accomplishments, instrumental per-
formances and song, by bodily charms, natural beauty, or
artificial decoration. But by far the most important of these
different forms of sexual selection in man is that form which
is the most exalted, namely, psychical selection, in which the
mental excellences of the one sex influence and determine
the choice of the other. The most highly intellectually de-
veloped types of men have, throughout generations, when
choosing a partner in life, been guided by her excellences
of soul, and have thus transmitted these qualities to their
posterity, and they have in this way, more than by any
other thing, helped to create the deep chasm which at present
separates civilized men from the rudest savages, and from
our common animal ancestors. In fact, both the part played
by the prevalence of a higher standard of sexual selection,
and the part played by the due division of labour between
the two sexes, is exceedingly important, and I believe that
here we must seek for the most powerful causes which have
determined the origin and the historical development of the
races of man. Darwin, in his exceedingly interesting work,
published in 1871, on " The Descent of Man and Sexual
Selection," 48 has discussed this subject in the most masterly
manner, and has illustrated it by most remarkable examples.
The immense value which the struggle for existence, and
natural selection as its consequence, possesses for the de-
velopment of organic nature, has been recognized more and
more during the thirty years since its first discovery by
Darwin. However, this struggle has usually been conceived

EOUX'S THEORY. 291

•

only in connection with the life and construction of the
individual organisms. But of no less importance, indeed of
even greater and more general importance, is that struggle
for existence which takes place everywhere and at all
times between all the different constituent parts of the
organism ; its transformation is, in fact, only the total
result of the peculiar development of all its constituent
parts.

Darwin himself never broached the question of these
elementary, structural transformations. The first compre-
hensive account and critical explanation of these elementary
transformations was presented in 1881 by Professor Wilhelm
Roux, of Breslau, in his admirable work, " The Struggle of
the Parts in Organisms : a Contribution towards the Com-
pletion of the Doctrine of the Mechanical Origin of what is
Suitable." I consider this work as one of the most important
contributions to the doctrine of development that has
appeared since Darwin's chief work (1859), and as one of
the most essential supplements to his theory of selection.
In the first part of his work Eoux discusses the functional
adaptation of the several organs, and the transmissibility of
these effects, more especially the functional self-formation
of suitable structures, and explains them as a necessary
result of the increase or lessening of habits (compare above,
p. 221). In the second portion of his work he investigates the
struggle of the parts in the organism, and shows that the
inequalities of the parts, the unequal relations of their
activity and nutrition, and of the change of their substance
and growth, must necessarily lead to a struggle among them
for existence ; and that this applies as much to the several
organs, and to the tissues of which they are composed, as

292 THE HISTOEY OF CREATION.

to the single cells of which the organs are composed, and
finally even to the active molecules of which the plasma of
the cells and their kernels are composed (Plastidules or
Micells). The correlation between the division of labour
(or the physiological function) of every single part and its
nutrition is of great importance here ; for while every
functional irritation reacts upon the change of substance of
the active part, and thus accomplishes a " trophic effect," it
at the same time causes variations in its form and structure
(that is morphological differentiations). Hence Roux traces
Adaptation, in its widest sense, back to the vital activity of
nutrition, as I had already done in 1866, in my " General
Morphology."

By means of numerous excellent examples, Roux points
out that the increased activity of an organ strengthens its
speeial functional capacity, whereas, on the contrary, a
lessened activity will diminish it (in Lamarck's sense) ; and
further, that through the influence of functional stimulus
parts that appear designed for a definite purpose, and
which have attained the highest conceivable perfection, are
produced and formed in a directly mechanical way, without
any other final cause, with a purpose, coming into play.
This gives a most simple explanation of the remarkable per-
fection in the delicate structure of the bones, muscles, blood-
vessels, etc., that appear so extremely suitable for definite
purposes. The minute supporting plates of the bones run
in the direction of the stronger pressure and drag, and thus,
with the smallest amount of material, acquire the greatest
amount of supporting force; the delicate fibres of the
muscles of the flesh run only in the direction in which
their contraction takes place; and when muscular tubes

CELLULAR SELECTION. 293

(for instance, the intestines, blood-vessels) contract in two
directions, in length and in breadth, the fibres of the muscles
arrange themselves only in these two directions. In like
manner, also, the more delicate structure of the nerves, the
blood-vessels, the glands, etc., are adapted in the most
suitable manner for their peculiar activity. Looked at from
a purely mechanical point of view, the relations of their
structure appear to be arrangements of the most perfect
design for a given purpose that can be conceived ; and yet
they have been produced without any pre-ordained purpose,
— in fact, in a purely, mechanical manner, by means of the
peculiar activity of the organs themselves in connection
with their functional stimulus.

The very important principle of the functional self-
formation of suitable parts, which Roux has explained
so clearly, shows us that the actual, existing suitableness
of the internal structure of the body has to be traced back
to teleological mechanism. But even this can again be
explained by the principle of selection ; not, however, in
Darwin's sense of the word, that it is produced by the
struggle for existence between independent individuals, but
in the sense in whieh Roux uses the word, and according to
which the struggle is continually active in all the parts of
the single organism.

Hence the selection of cells, which according to Roux
takes place everywhere in the tissues, might be termed
Cellular Selection, in opposition to the Personal Selection
whieh Darwin first pointed out between independent
individuals. The former principle would stand in the same
relation to the latter as Virchow's Cellular Pathology stands
to Personal Pathology, or my Cellular Psychology to Per-

294 THE HISTORY OF CREATION.

sonal Psychology (compare my lecture on "Cell souls
and Soul-cells"). The key to the right understanding
of this relation lies in the Theory of Cells, and in the far-
reaching progress which this fundamental theory has made
during the last half-century (especially during the last
three decades). We now no longer look upon organic cells as
dead building-stones, but as living " elementary organisms,"
as Plastids or constructural units.

All independent individuals, and, indeed, both morpho-
logically (as regards structure of the body) as well as
physiologically (as regards vital activity), are originally
cells. But nevertheless there is a great difference between
the one-celled organisms (Protista) and the many-celled
(Histones). In the Protista, or the one-celled forms of life
(primary plants and primary animals), the single cell
constitutes the whole organism throughout its life. In the
histons, on the other hand, the many-celled animals and
plants, the organism consists only at the commencement
of its existence of a single cell ; as soon as this cell begins
to develop, it increases by repeated division, and the
numerous cells that arise constitute the tissues and organs.
In the histons the sociably connected cells are dependent
upon one another and upon the whole organism, and are so
all the more, the more highly developed the organism is,
i.e. the more strongly it is centralized. Hence the one-
celled Protist stands in much the same relation to the
many-celled and tissue-forming histon as a single man does
to the community. The many-celled organism is a com-
munity of cells, and its single cells are the members of the
community (compare Chapters VIII. and XVII.).

Accordingly, al] the vital activities in the two main

CELLULAR SELECTION. 295

groups of one-celled and many-celled organisms show
certain specific differences ; the same will be found also in
their activity in the struggle for existence, in the interaction
of inheritance and adaptation which thereby acts selectively.
The one-celled organisms, or Protista, show a simple (or
trophic) growth, by cell-enlargement ; they increase, for the
most part, in a non-sexual manner (by division or the for-
mation o£ spores). Inheritance is, therefore, accomplished
by the kernel of the one cell, which at the same time
constitutes the whole organism. The many-celled organisms,
or histons, on the other hand, show a composite (or numerical)
growth, by cell-increase ; they reproduce themselves in a
sexual manner (by the commingling of egg-cell and sperm-
cell). Inheritance is, therefore, effected only by the kernels
of the two sexual cells, whereas the other tissue-cells take
no part in it. But within the tissue there is also a con-
tinual increase of the cells of which it is composed ; and the
formation of the tissue itself is determined by the cellular
selection, which we have just spoken of as a highly im-
portant principle. The sturdiest cells in each tissue, those
that perform their work best, seek and obtain, as a return,
the best portion of the nutritive juice ; they withdraw it
from the weaker and less sturdy cells : the former grow and
increase by division, whereas the latter must sooner or
later die off.

The struggle for existence between the tissue-cells of
the many-celled organisms must, accordingly, be regarded
as the most important stimulus towards the progressive
development and differentiation of their tissues and organs.
In the case of one-celled organisms, on the other hand, the
struggle for existence, and the natural selection occasioned

296 THE HISTORY OP CREATION.

by it, assumes an essentially different form. For in this
case, of course, there is no question of the formation of
tissues ; the formation of the independent cell that remains
independent is determined partly and directly by the
influence of the outward conditions of existence, partly by
the counteraction exercised by the Plastidules or Micells —
the active, living plasma-molecules of the cell. We may
even assume a constant struggle for existence between these
latter ; and Koux has shown what great importance has to
be ascribed to it in regard to change of substance and the
nutrition, hence also as regards adaptation and the forma-
tion of the elementary organism. However, this molecular
selection is just as hypothetical, and as little demonstrable,
as the molecular structure which we have to assume (in
some form or another) for the plasma. As an hypothesis it
is indispensable, and, moreover, both as regards the inde-
pendent one-celled Protista and for the dependent tissue-
cells of the Histories.

The more deeply we have recently penetrated into these
elementary relations of organic life, and the more we have
become acquainted with their intricate correlations, the
more highly we have learnt to appreciate the value of the
theory of selection, and the grander appears to us Darwin's
philosophical and scientific work. For by founding the
theory of selection on the struggle for existence, he not only
discovered the most important cause of the formation and
transformation of organic forms, but he at the same time
gave a conclusive answer to one of the greatest philosophical
problems, viz. the question as to how arrangements serving
a purpose can arise mechanically without causes acting
for a purpose.

EMPEDOCLES. 297

An endeavour to answer this difficult fundamental ques-
tion, in accordance with nature, was made as early as the
fifth century before Christ, by Empedocles of Agrigentum,
the great Greek philosopher. According to him, the forms
of animals and plants that serve a purpose, and as we now
know them, originated only gradually, and, moreover, owing
to the continual struggle of opposing forces of nature ; the
present living forms he considered the remains of an im-
mensely large number of extinct forms, and, indeed, because
they were most advantageously adapted for that struggle,
and hence were the most suitable survivors. Empedocles,
on the one hand, lays special emphasis on the fact that the
structure of the bodies of living creatures serve a purpose ;
but, on the other hand, he at the same time points out that
we must not set up any " principle of intentional design "
in explanation of them, as they have arisen in a purely
mechanical way by the interaction of natural forces. Fritz
Schultze, therefore, in his account of Greek philosophy,
justly says, " To have first conceived the grand thought of
a theory of tracing the origin of what is suitable from what
is unsuitable, is the brilliant merit of Empedocles, and when
we consider that his two fundamental principles, love and
hate, are the germinal forms of the modern fundamental
forces of attraction and revulsion, we cannot assuredly
deny Empedocles, the early investigator of nature, our full
admiration."

Hence, as regards the solution of this most important
question, Empedocles must be regarded as Darwin's earliest
predecessor. For although other philosophers of nature, in
classic antiquity, especially Lucretius, recognized the great
significance of the question, still it was subsequently alto-

298 THE HISTORY OF CREATION.

gether forgotten. Even Kant — as was shown in a preceding
chapter — so little estimated its true value, that he con-
sidered it absurd even to hope of ever being able to solve
the question : " we must, in fact, deny that man can ever
gain further insight into the matter."

But as Charles Darwin, by means of his theory of selec-
tion, has actually solved this most weighty fundamental
question, he has, I repeat it, become a new Newton, the
possibility of whose coming Kant considered himself justified
in denying for ever. Short-sighted naturalists have, indeed,
declared this comparison exaggerated and ridiculous, but
have only shown how little they are capable of estimating
the philosophical value of Darwinism. For the problems,
as well as the means for answering them, were incom-
parably simpler in the case of Newton's theory of gravita-
tion than in Darwin's theory of selection. For which
reason, also, the natural truth of the former theory is at
once evident to every cultivated mind, whereas thorough
scientific study is necessary for the full appreciation and
understanding of the theory of selection. Both, however,
have rendered service of equal value, by having cast out the
supernatural idea of purposeness in nature, and the miracles
associated with it, from the domain of our scientific know-
ledge — Newton from the anorganic domain, and Darwin
from the domain of organic nature.

The speculative philosophy of recent times has become
more and more convinced of the necessity of retracing
its steps from the Icarian cloudland of "pure specula-
tion" to the firmer ground of the empiric knowledge of
nature, and especially of comprehending the important
biological advances of the last generation. Thus Wundt,

IMPORTANCE OF DARWINISM. 299

Fritz Schultze, G. H. Schneider, B. von Carneri, Spitzer,
and others have of late been zealously endeavouring to
form a proper estimate of the philosophical significance of
Transformism, and in drawing the most important conclu-
sions from Darwin's theories. And Darwinism also forms
the basis of the monistic philosophy of Herbert Spencer,
Jacob Moleschott, Ludwig Biichner, and others. Hugo
Spitzer, especially, has ably pointed out the value of the
theory of selection, and how it has thrown a perfectly new
light on " teleology in the conception of the world of
organisms." Spitzer's " Contributions to the Theory of
Descent and to the Methodology of Natural Science " (1886)
is, as yet, the fullest attempt correctly to estimate the
philosophical importance of Darwinism. It sets aside the
supernatural and dualistic " transcendental idea of purpose-
ness;" it gives us in its place the natural and monistic
principle of " teleological mechanism."

300 THE HISTORY OF CREATION.

CHAPTER XII.

DIVISION OF LABOUR AND DIVERGENCE OF FORMS.
PROGRESS AND RETROGRADATION.

Division of Labour (Ergonomy) and Divergence of Forms (Polymorphism).
— Physiological Divergence and Morphological Differentiation both
necessarily determined by Selection. — Transition of Varieties into
Species. — The Idea of Species. — Hybridism. — Personal Divergence and
Cellular Divergence. — Differentiation of the Tissues. — Primary and
Secondary Tissues.— Siphonophora. — Change of Labour (Metergy). —
Convergence. — The Law of Progress and Perfeotioning. — The Laws of
the Development of Mankind. — The Eelation between Progress and
Divergence. — Centralization as Progress. — Retrogradation. — The Origin
of Rudimentary Organs by Non-Use and Habits discontinued. — The
Doctrine of Puirposelessness, or Dysteleology.

When we contemplate the historical development of the
organic world in its entirety, we meet with, in the first place
as the most general phenomena, two great laws, the law
of Divergence and the law of Progress. The principle of
Divergence or Separation teaches us, in the first place, as a
fact — based upon our knowledge of petrifactions — that the
variety and difference of the living forms on our earth has
continually increased from the earliest times up to the
present. The second principle, that of Progress or of Per-
fectioning, teaches us — on the same basis of palaeontological
records — that this divergence has, upon the whole, been

DIVISION OF LABOUR. 30 1

connected with continual progress, with an increasing state
of perfection in the organization. The foundation of both
these laws rests, in the first place, for the most part in the
physiological Division of Labour in organisms (Ergonomy),
and in the morphological Separation or Divergence of Forms
(Polymorphism) connected with it.

When the general application of these two great historical
principles were first recognized, after a series of very exten-
sive palseontological investigations, it was thought that the
origin of these laws must be looked for in some definite
plan of creation, or directly in some supernatural intention.
It was supposed to be part of the plan of a Creator, acting
for a definite purpose, in the course of time to develop the
forms of animals and plants more and more variously, and
to bring them more and more to a state of perfection. We
shall evidently make a great advance in the knowledge of
nature if we reject this teleological and anthropomorphic
conception, and if we can prove the two laws of Division of
Labour and Perfecting to be the necessary consequences of
natural selection in the struggle for life.

The first great law which follows directly and of necessity
from natural selection is, that of separation or differentia-
tion, frequently also called division of labour (Ergonomy),
or separation of forms (Polymorphism) ; Darwin calls this
same general principle divergence of character. We under-
stand by it the general tendency of all organic individuals
to develop themselves more and more diversely, and to
deviate from the common primary type. The cause of this
general inclination towards differentiation, and the forma-
tion of heterogeneous forms from homogeneous beginnings,
is, according to Darwin, to be traced simply to the circum-

302 THE HISTORY OF CBEA.TIOK.

stance that the struggle for life between every two
organisms rages all the more fiercely the nearer the relation
in which they stand to one another, or the more nearly
alike they are. This is an exceedingly important, and in
reality an exceedingly simple relation, but it is usually not
duly considered.

It must be obvious to every one that in a field of a
certain size, besides the corn-plants which have been sown,
a great number of weeds can exist, and, moreover, in places
which could not have been occupied by corn-plants. The
more dry and sterile places of the ground, in which no
corn-plant would thrive, may still furnish sustenance to
weeds of different kinds ; and such species and individuals
of weeds will more readily be able to exist in such con-
ditions, in proportion as they are suited to adapt themselves
to the different parts of the ground. It is the same with
animals. It is evident that a much greater number of
animal individuals can live together in one and the same
limited district, if they are of various and different natures,
than if they are all alike. There are trees (for example,
the oak) on which a couple of hundred of different species
of insects live together. Some feed on the fruits of the
tree, others on the leaves, others again on the bark, the
root, etc. It would be quite impossible for an equal number
of individuals to live on this tree if all were of one species ;
if, for example, all fed on the bark, or only upon the leaves.
Exactly the same is the case in human society. In one and
the same small town, only a certain number of workmen
can exist, even when they follow different occupations.
The division of labour, which is of the greatest use to the
whole community, as well as to the individual workman, is

DIVERGENCE OF CHARACTERS. 303

a direct consequence of the struggle for life, of natural
selection; for this struggle can be sustained more easily
the more the activities, and hence, also, the forms of the
different individuals deviate from one another. The dif-
ferent function naturally produces its reaction in changing
the form, and the physiological division of labour necessarily
determines the morphological differentiation, that is, the
" divergence of character." 87

Now, I beg the reader again to remember that all species
of animals and plants are variable, and possess the capability
of adapting themselves to different places or to local rela-
tions. The varieties or races of each species, according to
the laws of adaptation, deviate all the more from the original
primary species, the greater the difference of the new con-
ditions to which they adapt themselves. If we imagine
these varieties — which have proceeded from a common
primary form — to be disposed in the shape of a branching,
radiating bunch, then those varieties will be best able to
exist side by side and propagate which are most distant
from one another, which stand at the ends of the series, or
at the opposite sides of the bunch. Those forms, on the
other hand, occupying a middle position — presenting a state
of transition — have the most difficult position in the struggle
for life. The necessaries of life differ most in the two ex-
tremes, in the varieties most distant from one another, and
consequently these will get into the least serious conflict
with one another in the general struggle for life. But the
intermediate forms, which have deviated less from the
original primary form, require nearly the same necessaries
of life as the original form, and therefore, in competing
for them, they will have to struggle most with, and be

304 THE HISTOEY OF CREATION.

most seriously threatened by, its members. Consequently,
when numerous varieties of a species live side by side on
the same spot of the earth, the extremes, or those forms
deviating most from one another, can much more easily
continue to exist beside one another than the intermediate
forms which have to struggle with each of the different
extremes. The intermediate forms will not be able to
resist, for any length of time, the hostile influences which
the extreme forms victoriously overcome. These alone
maintain and propagate themselves, and at length cease to
be any longer connected with the original primary species
through intermediate forms of transition. Thus arise " good
species " out of varieties. The struggle for life necessarily
favours the general divergence of organic forms, that is, the
constant tendency of organisms to form new species. This
fact does not rest upon any mystic quality, or upon an
unknown formative tendency, but upon the interaction of
Inheritance and Adaptation in the struggle for life. As
the intermediate forms, that is, the individuals in a state of
transition, of the varieties of every species die out and
become extinct, the process of divergence constantly goes
further, and the extremes develop forms which we dis-
tinguish as new species.

Although all naturalists have been obliged to acknowledge
the variability and mutability of all species of animals and
plants, yet most of them have hitherto denied that the
modification or transformation of the organic form surpasses
the original limit of the characters of the species. Our
opponents cling to the proposition — " However far a species
may exhibit deviations from its usual form in a collection
of varieties, yet the varieties of it are never so distinct from

GOOD AND BAD SPECIES. 305

one another as two really good species." This assertion,
which Darwin's opponents usually place at the head of
their arguments, is utterly untenable and unfounded. This
will become quite clear as soon as we critically compare the
various attempts to define the idea of species. No naturalist
can answer the question as to what is in reality a " genuine
or good species " (" bona species ") ; yet every systematic
naturalist uses this expression every day, and whole libraries
have been written on the question as to whether this or
that observed form is a species or a variety, whether it is a
really good or a bad species. The most general answer to
this question used to be the following: "To one species
belong all those individuals which agree in all essential
characteristics. Essential characteristics of species are
those which remain permanent or constant, and never
become modified or vary." But as soon as a case occurred
in which the characteristic — which had hitherto been con-
sidered essential — did become modified, then it was said,
"This characteristic is not essential to the species, for
essential characteristics never vary." Those who argued
thus evidently moved in a circle, and the naivete with
which this circular method of defining species is laid down
in thousands of books as an unassailable truth, and is still
constantly repeated, is truly astonishing.

All other attempts which have been made to arrive at a
definite and logical determination of the idea of organic
" species " have, like the last, been utterly futile, and led to
no results. Considering the nature of the case, it cannot
be otherwise. The idea of species is just as truly a relative
one, and not absolute, as is the idea of variety, genus, family,
order, class, etc. As Lamarck maintained, already in 1809,

vol. 1. X

306 THE HISTOEY OF CREATION.

all these ideas are subjective and artificial. I have proved
this in detail in the criticism of the idea of species in my
" General Morphology " (" Gen. Morph." ii. 323-364). Prac-
tically I proved this in my " System of Calcareous Sponges "
in 1872. In the case of these remarkable animals, as in
sponges generally (even in the Bath-sponge), the usual
distinction of species appears altogether arbitrary.

As arbitrary and unnatural have been the opinions
hitherto formed of the relation of species to hybridism.
Formerly it was regarded as a dogma that two good species
could never produce hybrids which could reproduce them-
selves as such. Those who thus dogmatized almost always
appealed to the hybrids of a horse and donkey, the mule
and the hinny, which, truly enough, are seldom able to
reproduce themselves. But the truth is that such unfruit-
ful hybrids are rare examples, and in the majority of cases
hybrids of two totally different species are fruitful and able
to reproduce themselves. They can almost always fruit-
fully mix with one or other of the parent species, and
sometimes also among themselves ; and in this way com-
pletely new forms can originate according to the laws of
"mixed transmission by inheritance" (compare above,
p. 216).

Thus, in fact, hybridism is a source of the origin of new
species, distinct from the source we have hitherto considered
— natural selection. I have already spoken occasionally
of these hybrid species (species hybridse), especially of the
hare-rabbit (Lepus Darwinii), which has arisen from the
crossing of a male hare and a female rabbit ; the goat-sheep
(Capra ovina), which has arisen from the pairing of a he-
goat and ewe ; also the different species of thistles (Cirsium),

ORIGIN OF NEW SPECIES. 307

brambles (Rubus), etc. It is possible that many wild species
have originated in this way, as even Linnaeus assumed.
This supposition appears especially justifiable as regards
many of the lower sea-plants and sea^animals, whose rich
sexual products are simply emptied into the water. Their
commingling and fructification is left to chance; and the
active agility of most of these freely swimming seed-cells
must specially be taken into consideration. Now, we know
by many observations and experiments that the fructifica-
tion of the egg-cells is often more easily accomplished by
the crossing of two closely related species, than in the case
of individuals of the same species. Hence it is very probable
that the chance meetings of innumerable seed-cells and egg-
cells of closely related marine creatures give rise: to more
hybrids than to products of pure in-breeding; and as the
former, moreover, are frequently more prolific than the latter,
they may easily push the others aside in the struggle for
existence, and form new species. Of late years Weismann,
above all others, has emphasized the high importance of
sexual commingling for the transformation of species. At
all events, these hybrid species, which can maintain and
propagate themselves as well as pure species, prove that
hybridism cannot serve in any way to give an absolute
definition to the idea of species.

I have already mentioned (p. 141) that the many vain
attempts to define the idea of species theoretically have
nothing whatever to do with the practical distinction of
species. The extensive practical application of the idea of
species, as it is carried out in systematic zoology and botany,
is very instructive as furnishing an example of human folly.
Hitherto, by far the majority of zoologists and botanists, in

308 THE HISTORY OP CREATION.

distinguishing and describing the different forms of animals
and plants, have endeavoured, above all things, to dis-
tinguish accurately kindred forms as so many "good
species." However, it has been found scarcely possible, in
any group, to make an accurate and consistent distinction
of such "genuine or good species." There are no two
zoologists, no two botanists, who agree in all cases as to
which of the nearly related forms of a genus are good
species, and which are not. All authors have different
views about them. In the genus Hieraciwm, for example,
one of the commonest genera of European plants, no less
than 300 species have been distinguished in Germany alone.
The botanist Fries, however, only admits 106, Koch only 52,
as "good species," and others accept scarcely 20. The
differences in the species of brambles (Rubus) are equally
great. Where one botanist makes more than a hundred
species, a second admits only about one half of that number,
a third only five or six, or even fewer species. The birds
of Germany have long been very accurately known.
Bechstein, in his careful "Natural History of German
Birds," has distinguished 367 species, L. Reichenbach 379,
Meyer and Wolff 406, and Brehm, a clergyman learned in
ornithology, distinguishes even more than 900 different
species. With regard to the Calcareous Sponges, I have
myself shown that these exceedingly variable zoophytes can,
at will, be distinguished as 3 species, or 21, or 111, or 289,
or even 591 species. As it was impossible for me in this
Monography to distinguish "good species" in the usual
sense of the word, my work might as well be considered
" An Attempt at an Analytical Solution of the Problem of
the Origin of Species," for I devoted five years. of most

OEIGIN OP NEW SPECIES. 309

careful study to the subject with very perfect material.
No other attempt of the kind has hitherto been made with
the same degree of completeness.

Thus we see that here, and, in fact, in every other domain
of systematic zoology and botany, the most arbitrary pro-
ceedings prevail, and, from the nature of the ease, must
prevail. For it is quite impossible accurately to distinguish
varieties and races from so-called " good species." Varieties
are commencing species. The variability or adaptibility of
species, under the influence of the struggle for life, necessi-
tates the continual and progressive separation or differentia-
tion of varieties, and the perpetual separation of new forms.
Whenever these are maintained throughout a number of
generations by inheritance, whilst the intermediate forms
die out, they form independent " new species." The origin
of new species by division of labour or separation, divergence
or differentiation of varieties, is therefore a necessary con-
sequence of natural selection.

That the constant disposition of organisms to separate or
diverge in form in this manner, must be a necessary con-
sequence of natural selection, Darwin himself was the first
to perceive; and he has convincingly proved this in the
fourth chapter of his chief work. However, he applies his
principle of divergence as well as his principle of selection,
mainly only to independently living creatures, and en-
deavours to show how the variations of the individuals
lead to the origin of new species by selection and divergence.
Now, in our last chapter, we have seen that the theory
of selection can be much more extensively and generally
applied by the fact that all the single parts in the organism,
and, above all, the cells, can be transformed by selection.

3IO THE HISTORY OF CREATION.

This cellular selection appears by the side of personal
selection as an extremely important process of transforma-
tion, and the same will be found to be the case also -with
the theory of divergence ; for personal divergence finds its
elementary foundation in the differentiation of the cells,
which constitute the individual person, that is, in cellular
divergence.

The theory of the tissues of animals and plants (that is,
histology) has long since recognized, from the theory of
cells, that one of the most important phenomena in the
development of the histons, or many-celled organisms, is the
so-called differentiation or separation of the tissues. By
this we understand, generally speaking, the fact which
strikes us at once in the development of every many-celled
individual, that homogeneous cells produce heterogeneous
tissues. From the homogeneous cells of the germ-layers
(for instance, in all metazoa or many-celled animals) there
develop cells of entirely different kinds, which form the
skin, the glands, the connecting tissues, the muscles, the
nerves, etc. Thus we can convince ourselves, at the same
time, that the original form of tissue in the animal body is
a simple layer of cells, or an epithelium; even the first
development of germ-skin (blastoderm) is an epithelium of
this kind (see Plate V., Fig. 5, 6). And the falling in
of the blastula (Fig. 7) gives rise to the gastrula (Fig. 8),
and the simple germ-skin separates into the two so-called
" primary germ-layers," the exoderm (e) and the entoderm (i).
From the latter, by further separation, are produced the
four secondary germ-layers (likewise simple epithelium,
Fig. 9), and from these again all the various kinds of tissue.
These latter, therefore,, must.. all he termed "secondary

THE SIPHONOPHOKA. 311

tissue," in contrast to the primary tissue' of the epithelium
out of which they arose.

The whole of this important process, the so-called
differentiation of the tissues, is in reality nothing but a
divergence of the cells, which constitute the tissues. Its
physiological nature is determined by the division of labour
of the cells; its morphological result is the divergence of
form in the cells, or the unequal formation of the cells
which were originally equal. But this divergence of form
(Polymorphism) as well as the division of labour (Ergonomy)
are both the necessary consequence of cellular selection, or
of that struggle of parts in the organism which Roux was
the first to recognize in its full importance (see above,
p. 291).

In my lecture " On the Division of Labour in Nature and
in Human Life," I pointed out the extraordinary importance
which the division of labour, and the divergence of forms
connected with it, possesses for the explanation of the most
different sides of oiganic life. And I there discussed in
detail the organization of the splendid Hood-jellies, the
Siphonophora, as a peculiarly remarkable example of this
division of labour. These Siphonophora are swimming
communities of medusae, which outwardly resemble a splendid
flowering plant ; the separate leaves, flowers, and fruit of
this plant, generally as transparent as coloured glass and
at the same time sensitive and agile in the highest degree,
appear at first sight merely the organs of one individual, or
of a single, peculiarly complex zoophyte. But, in reality,
every one of these apparent organs is originally a medusa
or hood-jelly, a single animal possessing the form- value of
one individual. By adaptation to different tasks in life,

312 THE HISTOEt OF CREATION.

these individuals and their organs have gradually become
transformed in the most remarkable manner; and as all
have remained in continual connection with the original
mother-animal, the central root of the stock, and as also the
food of the whole social community is the same, the numerous
separate animals appear merely as the organs of a single
individual.

However, the various forms of these Siphonophora
(which I have classified and compared carefully in my
Monography on this extremely interesting class of animals)
not only offers a wealth of instructive examples of the
division of labour and divergence of form, but are an example
also of the important phenomenon connected with these
others, namely, Change of Labour, or Change of Function
(Metergy). For as originally the homogeneous medusae
which formed the community of Siphonophora accustomed
themselves to different activities, and accordingly changed
their form, the various organs of the individual medusae must
frequently change their original species of activity. Thus,
for example, the original swimming organ of the medusae,
their muscular hood, changes in some of them into a peculiar
muscular swimming-bell, in others into a swimming-bladder
filled with air ; in a third group we find it in the form of a
protecting umbrella, in a fourth group in the form of a capor
hood, etc. The original simple alimentary tube of the
medusae changes in some of them into a most complex
gland-stomach (Siphon), in others into a very sensitive
apparatus of sense (Palpon) ; in the male animals into a
seed-case (Androphore), in the female individuals into an
egg-case (Gynophore), etc. The Siphonophora, accordingly,
teach us that change of labour is directly connected with

CHANGE OF FUNCTION. 313

division of labour, and that there is no need to set up any
" principle of the change of function."

Many of the most important changes in the organic
world, even the origin of whole classes of animals, may
be traced back to the change of labour, or the metergy
of the several organs. Thus, for instance, amphibious
animals have originated out of fish, by the swimming-
bladder of the fish (a hydrostatic organ) becoming a lung,
and by its undertaking the work of changing the gas
or breathing air; the transition from life in water to
life on land was the first inducement to do so. Birds
have originated out of lizard-like reptiles by the flying
movement having taken the place of creeping from place
to place. The fore legs of the latter became changed into
wings. Perhaps the chief cause of the origin of mammals
out of reptile-like primary forms was the change of labour
of the skin-glands on the belly side ; for by these secreting
glands (perspiring and fatty glands) changing into milk-
glands, and thus becoming the chief organ of nutrition
for the new-born individuals, they gave rise to a series
of the most important variations. The first cause that
led to the change was probably a habit contracted by the
new-born individual of licking the ventral skin of its
mother; the nutritive stimulus caused by this would in
the first place lead (quantitively) to the enlargement of the
skin-glands, and subsequently (qualitively) to their trans-
formation into the important mammary glands ; all the
problems of civilization (especially of art) that are connected
with the female bosom may be phylogenetically traced
back to that proceeding. But the change of labour has
also been of great importance for the origin of the human

3H THE HISTORY OF CREATION.

race, more especially the division of labour undertaken by
the fore and hind limbs, and the metergy of the former
connected with it; for whereas in climbing monkeys (or
Quadrumana) all the four limbs remain similar in form and
function, in man, who walks upright, the fore limbs took
the form of arms for grasping, the back limbs the form of
legs for walking. The divergence between the former and
the latter led to the development of the human hand, that
invaluable instrument of art, whose manifold changes of
labour have become the source of the most marvellous
accomplishments, as in the painter and sculptor, the pianist
and other artists, in the doctor and surgeon ; even the
division of labour and change of labour in the individual
fingers, as is well-known, plays a significant part here.

A series of important phenomena, which appear to stand
opposed to those of divergence or separation, are those of
so-called convergence or resemblance. For while divergent
selection makes forms that are perfectly alike absolutely
different in the end by adaptation to changed conditions of
life and activity, convergent selection, on the other hand,
makes forms which were originally altogether different
become extremely alike by adaptation to similar conditions
of existence and similar functions. Thus, for instance,
many fish and whales are externally extremely alike,
although the internal structure is entirely different. The
warm-blooded whales are genuine mammals, which have
assumed the form of fish by having adapted themselves
to their mode of life ; but they are descended from land
mammals, and, moreover, the herbivorous Sirenia, probably
from hoofed animals, the carnivorous dolphins and bearded
whales from rapacious animals. In these two groups,

CONVERGENT FORMS. 315

convergent selection has not only changed the external
form ; the inner structure too has become so alike, that they
were formerly classed as one order.

Another striking example of the convergence of character,
or similarity of form, is furnished by the medusae. This
apparently uniform class of animals consists of two entirely
distinct families, as I have shown in my Monography of
these zoophytes (1881). The smaller and neater polyp-
jellies (Oraspedota or Hydromedusae) are descended from
hydropolyps; the larger and more splendid flap-jellies
(Acraspedae or Scyphomedusae) are derived from scypho-
polyps ; the foi'm of development is -.likewise altogether
different in the two groups, and indeed both in an onto-
genetic and phylogenetic sense. Nevertheless the medusas
of both families have become so alike by adaptation to
a similar mode of life and the same activity of their
organs, that they are often not to be distinguished.

But in the vegetable world we have even more numerous
and more striking examples of deceptive resemblances
owing to adaptation. For instance, many water-plants are
distinguished by large, bare, flat, roundish leaves, which
float on the surface of ponds ; the genuine water-lilies
(Nymphseaceae) herein resemble many Potameae, Butomeae,
Alismaceae, Gentianeae, although these latter belong to
entirely different families. Further, numerous parasitic
plants, which are descendants of widely divergent families,
often become extremely alike — for instance, many orchids,
cytineae, labiate flowers, etc. Their adaptation to similar
parasitical ways of life produces in all the same disappear-
ance of green leaves, a peculiar fleshy development of the
stalk, flowers, etc. Such deceptive resemblance produced by

316 THE HISTORY OP CEBATION.

convergent selection has often led to great errors being
made in systematic classification.

All the phenomena of convergence or resemblance are,
therefore, very simply explained from the activity of natural
selection, in the same way as in the case of the phenomena
of division of labour or separation. The same also applies
to another very important series of phenomena, those of
progress (progressus) or perfecting (teleosis.) This great
law, like the law of differentiation, had long been empirically
established by palseontological experience, before Darwin's
Theory of Selection gave us the key to the explanation of
its cause. The most distinguished palaeontologists have
pointed out the law of progress as the most general result
of their investigations of fossil organisms. This has been
specially done by Bronn, whose investigations on the laws
of construction and the laws of the development 19 of
organisms, although little heeded, are excellent, and deserve
most careful consideration. The general results of the law
of differentiation and the law of progress, at which Bronn
arrived by a purely mechanical hypothesis, and by exceed-
ingly accurate, laborious, and careful investigations, are
brilliant confirmations of the truth of these two great laws
which we deduce as necessary inferences from the theory of
selection.

The law of progress or of perfecting establishes the ex-
ceedingly important fact, on the ground of palseontological
experience, that in successive periods of this earth's history,
a continual increase in the perfection of organic formations
has taken place. Since that inconceivably remote period
in which life on our planet began with the spontaneous
generation of Monera, organisms of all groups, both collec-

THE LAW OF PROGRESS. 317

tively as well as individually, have continually become
more perfectly and highly developed. The steadily increas-
ing variety of living forms has always been accompanied
by progress in organization. The lower the strata of the
earth in which the remains of extinct animals and plants
lie buried, that is, the older the strata are, the more simple
and imperfect are the forms which they contain. This
applies to organisms collectively, as well as to every single
large or small group of them, setting aside, of course, those
exceptions which are due to the process of degeneration,
which we shall discuss hereafter.

As a confirmation of this law I shall mention only the
most important of all animal groups, the tribe of vertebrate
animals. The oldest fossil remains of vertebrate animals
known to us belong to the lowest class, that of Fishes.
Upon these there followed later more perfect Amphibious
animals, then Reptiles, and lastly, at a much later period,
the most highly organized classes of vertebrate animals,
Birds and Mammals. Of the latter only the lowest and
most imperfect forms, without placenta, appeared at first,
such as the pouched animals (Marsupials), and afterwards,
at a much later period, the more perfect mammals, with
placenta. Of these, also, at first only the lower kinds
appeared, the higher forms later; and not until the late
tertiary period did man gradually develop out of these last.

If we follow the historical development of the vegetable
kingdom we shall find the same law operative there. Of
plants there existed at first only the lowest and most im-
perfect classes, the Algae or tangles. Later there followed
the group of Ferns or Filicinse (ferns, pole-reeds, scale-
plants, etc.). But as yet there existed no flowering plants,

318 THE HISTORY OF CBEATION.

or Phaherogama. These originated later with the Gyrimo-
sperms (firs and cycads), whose whole structure stands far
below that of the other flowering plants (Angiosperms), and
forms the transition from the group of fern-like plants to
the Angiosperms. These latter developed at a still later date,
and 'among them there were at first only flowering plants
without corolla (Monocotyledons and Monochlamyds) ; only
later were there flowering plants with a corolla (Diehlamyds).
Finally, again, among these the lower polypetalous plants
preceded the higher gamopetalous plants. The whole series
thus constitutes an irrefutable proof of the great law of
progressive development.

Now, if we ask what is the cause of this fact, we again,
just as in the case of differentiation, come back to natural
selection in the struggle for life. If once more we consider
the whole process of natural selection, how it operates
through the complicated interaction of the different laws
of Inheritance and Adaptation, we shall recognize not only
divergence of character, but also the perfecting of structure
to be the direct and necessary result of it. We can trace
the same thing in the history of the human race. Here,
too, it is natural and necessary that the progressive division
of labour constantly furthers mankind, and urges every
individual branch of human activity into new discoveries
and improvements. This progress itself universally depends
on differentiation, and is consequently, like it, a direct result
of natural selection in the struggle for life.

If man wishes to understand his position in nature, and
to comprehend as natural facts his relations to the phenomena
of the world cognizable by him, it is absolutely necessary
that he should compare human with extra-human phenomena,

THE HISTOEY OP NATIONS. 319

and, above all, with animal phenomena. We have already
seen that the exceedingly important physiological laws of
Inheritance and Adaptation apply to the human organism
in the same manner as to the animal and vegetable kingdoms,
and in both cases interact with one another. Consequently,
natural selection in the struggle for life transforms human
society, just as it modifies animals and plants, and in both
cases constantly produces new forms. The comparison of
the phenomena of human and animal transformation is
especially interesting in connection with the laws of diver-
gence and progress, when the two fundamental laws are
regarded as the direct and necessary consequences of natural
selection in the struggle for life.

A comparative survey of the history of nations, or what
is called " universal history," will readily yield to us, as the
first and most general result, evidence of a continually
increasing variety of human activities, both in the life of
individuals and in that of families and states. This differen-
tiation or separation, this constantly increasing divergence
of human character and the form of human life, is caused
by the ever-advancing and more complete division of labour
among individuals. While the most ancient and lowest
stages of human civilization show us throughout the same
rude and simple conditions, we see in every succeeding
period of history, among different nations, a greater variety
of customs, practices, and institutions. The increasing divi-
sion of labour necessitates an increasing variety of forms
corresponding to it. This is expressed even in the for-
mation of the human face. Among the lowest tribes of
nations, most of the individuals resemble one another so
much that European travellers often cannot distinguish

320 THE HISTORY OF CREATION.

them at all. With increasing civilization the physiognomy
of individuals becomes so differentiated, that, even among
individuals all of the same race, we very rarely mistake one
face for another.

The second great fundamental law, obvious in the history
of nations, is the great law of progress or perfecting. Taken
as a whole, the history of man is the history of his 'progres-
sive development. It is true that everywhere and at all
times we may notice individual retrogressions, or observe
that crooked roads towards progress have been taken, which
lead only towards one-sided and external perfecting, and
thus deviate more and more from the higher goal of internal
and enduring perfecting. However, on the whole, the
movement of development of all mankind is and remains
a progressive one, inasmuch as man continually removes
himself further from his ape-like ancestors, and continually
approaches nearer to his own ideal.

The mighty retrogression which is found existing during
the darkness of the Middle Ages, as compared with the
brilliant light of classic antiquity, is sometimes brought
forward to oppose the importance of the law of progress.
But, apart from the fatal internal and external causes
which necessarily led to the unfortunate destruction of the
light of classic antiquity, the retrogression during the Middle
Ages was for the most part occasioned by the contempt of
nature which Christianity preached, and the tyrannical
rule which its all-powerful hierarchy exercised over every
form of independent mental activity. And yet, even during
this dark period of history, many germs of a new life were
active in secret, and, after the Reformation, appeared as
new forms of culture. Besides this, however, the short

PROGRESS AND DIFFERENTIATION. 32 1

period of scarcely one thousand years, which comprises the
darkest epoch of the Middle Ages, seems, to the naturalist,
only a brief space of time compared with the many thou-
sands of years which — according to the latest investigations
into primseval times — have already passed since the appear-
ance of the human race.

Now, if we wish to know what causes actually determine
these two great laws of development in man, namely, the
law of divergence and the law of progress, we must compare
them with the corresponding laws of development in
animals, and on a close examination we shall inevitably
come to the conclusion that the phenomena, as well as their
causes, are exactly the same in the two cases. The course
of development in man, just as in that of animals, being
directed by the two fundamental laws of differentiation and
perfecting, is determined solely by purely mechanical causes,
and is solely the necessary consequence of natural selection
in the struggle for life.

Perhaps in the preceding discussion the question has pre-
sented itself to some — " Are not these two laws identical ?
Is not progress in all cases necessarily connected with diver-
gence?" This question has often been answered in the
affirmative, and Carl Ernst Bar, for example, one of the
greatest investigators in the domain of the history of de-
velopment, has set forth the following proposition as one of
the principal laws in the ontogenesis of the animal body :
" The degree of development (or perfecting) depends on
the stage of separation (or differentiation) of the parts." 20
Correct as this proposition may be on the whole, yet it is
not universally true. In many individual cases it can be
proved that divergence and progress by no means always

vol. 1. Y

322 THE HISTORY OF CREATION.

coincide. Every progress is not a differentiation, and every
differentiation is not a progress.

As regards the law of Progress or Perfecting, naturalists,
guided by purely anatomical considerations, had already set
forth the law that the perfecting of an organism certainly
depends, for the most part, upon the division of labour among
the individual organs and parts of the body, but that there
are also other organic transformations which determine a
progress in organization. One, in particular, which has
been generally recognized, is the numerical diminution of
identical parts. If, for example, we compare the lower
articulated animals of the crustacean group, which possess
numerous pairs of legs, and also the centipedes (Myrapoda),
with spiders which never have more than four pairs of legs,
and with insects which in all cases possess only three pairs
of legs, we find this law, for which a great number of
examples could be adduced, confirmed. The numerical
diminution of pairs of legs is a progress in the organization
of articulated animals. In like manner the numerical dimi-
nution of corresponding vertebral joints in the trunk of
vertebrate animals is a progress in their organization.
Fishes and amphibious animals with a very large number
of identical vertebral joints are, for this very reason, less
perfect and lower than birds and mammals, in which the
vertebral joints, as a whole, are not only very much more
differentiated, but in which the number of corresponding
vertebrae is also much smaller. Further, according to the
same law of numerical diminution, flowers with numerous
stamens are more imperfect than the flowers of kindred
plants with a smaller number of stamens, etc. If, therefore,
originally a great number of homogeneous parts exist in an

CENTBALIZATION. 323

organic body, and if, in the course of very many generations,
this number be gradually decreased, this transformation will
be an example of perfecting.

Another law of progress, which is quite independent of
differentiation, nay, even appears to a certain extent opposed
to it, is the law of centralization. In general the whole
organism is the more perfect the more it is organized as a
unit, the more the parts are subordinate to the whole, and
the more the functions and their organs are centralized.
Thus, for example, the system of blood-vessels is most perfect
where a centralized heart exists. In like manner, the dense
mass of marrow which forms the spinal cord of vertebrate
animals and the ventral cord of the higher articulated
animals, is more perfect than the decentralized chain of
ganglia of the lower articulated animals, and the scattered
system of ganglia in the molluscs. The community of
medusae, the Siphonophora, in the same way as a human
civilized community, is the more accomplished and the more
perfect, the more it is centralized. However, we must not
forget that the idea of perfection is relative only, not
absolute. Owing to the difficulty of explaining these
complex laws of progress in detail, I cannot here enter
upon a closer discussion of them, and must refer the reader
to Bronn's excellent " Morphologischen Studien," and to
my "General Morphology" ("Gen. Morph." i. 370, 550;
ii. 257-266).

While, therefore, we have, on the one hand, become
acquainted with phenomena of progress, quite independent
of divergence, we shall, on the other, very often meet with
divergencies which are no perfecting, but which are rather
the contrary, that is, retrogressions or degenerations. It is

324 THE HISTOKY OF CREATION.

easy to see that the changes which every species of animal
and plant experiences cannot always be improvements. In
fact, many phenomena of differentiation, which are of direct
advantage to the organism itself, are yet, in a wider sense,
detrimental, inasmuch as they lessen its general capabilities.
Frequently a relapse to simpler conditions of life takes
place, and by adaptation to them a divergence in a retro-
grade direction. If, for instance, organisms which have
hitherto lived independently accustom themselves to a
parasitical life, they thereby degenerate or retrograde. Such
animals, which hitherto had possessed a well-developed
nervous system and quick organs of sense, as well as the
power of moving freely, lose these when they accustom
themselves to a parasitical mode of life ; they consequently
retrograde more or less. There the differentiation viewed
by itself is a degeneration, although it is advantageous to
the parasitical organism. In the struggle for life such an
animal, which has accustomed itself to live at the expense
of others, by retaining its eyes and apparatus of motion,
which are of no more use to it, would only expend so much
material uselessly ; and when it loses these organs, then a
great quantity of nourishment, which was employed for the
maintenance of these parts, benefits other parts. In the
struggle for life between the different parasites, therefore,
those which make least pretensions will have advantage
over the others, and this favours their degeneration.

Just as this is found to be the case with the whole
organism, so it is also with the parts of the body of an
individual organism. A differentiation of parts, which
leads to a partial degeneration, and finally even to the loss
of individual organs, is, when looked at by itself, a degenera-

EYES OF CAVE-DWELLEKS. 325

tion, but yet may be advantageous to the organism in the
struggle for life. It is easier to fight when useless baggage
is thrown aside. Hence we meet everywhere, in the more
highly developed animal and vegetable bodies, processes of
divergence, which are in reality the cause of the degenera-
tion, and finally of the loss, of particular parts. And now
the most important and instructive of all the series of phe-
nomena bearing upon the history of organisms presents itself
to us, namely, that of rudimentary or degenerate, organs.

It will be remembered that even in my first chapter I
considered this exceedingly remarkable series of phenomena,
from a theoretical point of view, as one of the most important
and most striking proofs of the truth of the doctrine of
descent. We designated as rudimentary organs those parts
of the body which are arranged for a definite purpose and
yet are without function. Let me remind the reader of the
eyes of those animals which live in the dark, in caves and
underground, and which consequently never can use them.
In these animals we find real eyes hidden under the skin,
frequently developed exactly as are the eyes of animals
which really see; and yet these eyes never perform any
function, indeed cannot, simply for the reason that they
are covered by an opaque membrane, and consequently
no ray of light falls upon them. In the ancestors of these
animals, which lived in open daylight, the eyes were
well developed, covered by a transparent horny capsule
(cornea), and actually served the purpose of seeing. But
as the animals gradually accustomed themselves to an
underground mode of life, and withdrew from the daylight
and no longer used their eyes, these became degenerated.

Very clear examples of rudimentary organs, moreover, are

326 THE HISTORY OP CREATION.

the wings of animals which cannot fly ; for example, the
wings of the running birds, like the ostrich, emeu, casso-
wary, etc., the legs of which have become exceedingly
developed. These birds having lost the habit of flying,
have consequently lost the use of their wings ; however, the
wings are still there, although in a crippled form. "We very
frequently find such crippled wings in the class of insects,
most members of which can fly.

From reasons derived from comparative anatomy and
other circumstances, we can with certainty draw the
inference that all insects now living (all grasshoppers,
beetles, bees, bugs, flies, butterflies, etc.) have originated
from a single common parental form, from a primary insect
which possessed two well-developed pairs of wings, and
three pairs of legs. Yet there are very many insects in
which either one or both pairs of wings have become more
or less degenerated, and many in which they have even
completely disappeared. For example, in the whole order
of flies or Diptera, the hinder pair of wings — in the bee-
parasites or Strepsiptera, on the other hand, the fore pair
of wings — have become degenerated or entirely disappeared.
Moreover, in every order of insects we find individual
genera, or species, in which the wings have more or less
degenerated or disappeared. The latter is the case especially
in parasites. The females have frequently no wings, whereas
the males have; for instance, in the case of glow-worms
(Lampyris), Strepsiptera, etc. This partial or complete
degeneration of the wings of insects has evidently arisen
from natural selection in the struggle for life. For we find
insects without wings living under circumstances where
flying would be useless, or even decidedly injurious to

EUDIMENTABY OKGAXS. 327

them. If, for example, insects living on islands fly about
much, it may easily happen that when flying they are
blown into the sea by the wind, and if (as is always the
case) the power of flying is differently developed in different
individuals, then those which fly badly have an advantage
over those which fly well ; they are less easily blown into
the sea, and remain longer in life than the individuals of
the same species which fly well. In the course of many
generations, by the action of natural selection, this circum-
stance must necessarily lead to a complete suppression of
the wings. This conclusion might have been arrived at
on purely theoretical grounds, but here we find its truth
established by facts. For upon isolated islands the pro-
portion of wingless insects to those possessing wings is
surprisingly large, much larger than among the insects
inhabiting continents. Thus, for example, according to
Wollaston, of the 550 species of beetles which inhabit the
island of Madeira, 220 are wingless, or possess such imperfect
wings that they can no longer fly ; and of the 29 genera
which belong to that island exclusively, no less than 23
contain such species only. It is evident that this remark-
able circumstance does not need to be explained by the
special wisdom of the Creator, but is sufficiently accounted
for by natural selection, because in this case the hereditary
disuse of the wings, the discontinuance of flying in the
presence of dangerous winds, has been very advantageous
in the struggle for life. In other wingless insects the want
of wings has been advantageous for other reasons. Viewed
by itself, the loss of wings is a degeneration, but in these
special conditions of life it is advantageous to the organism
in the struggle for life.

328 THE HISTORY OF CREATION.

Among other rudimentary organs I may here, by way of
example, further mention the lungs of serpents and serpent-
like lizards. All vertebrate animals possessing lungs, such
as amphibious animals, reptiles, birds, and mammals, have
a pair of lungs, a right and a left one. But in cases where
the body is exceedingly thin and elongated, as in serpents
and serpent-like lizards, there is no room for the one lung by
the side of the other, and it is an evident advantage to the
mechanism of respiration if only one lung is developed. A
single large lung here accomplishes more than two small ones
side by side would do ; and consequently, in these animals,
we invariably find only the right or only the left lung fully
developed. The other is completely aborted, although exist-
ing as a useless rudiment. In like manner, in all birds the
right ovary is aborted and without function ; only the left
one is developed, and yields all the eggs.

I mentioned in the first chapter that man also possesses
such useless and superfluous rudimentary organs, and I
specified as such the muscles which move the ears. Another
of them is the rudiment of the tail which man possesses in
his 3 — 5 tail vertebrae, and which, in the human embryo,
stands out prominently during the first two months of its
development (compare Plates II. and III.). It afterwards
becomes completely hidden. The rudimentary little tail of
man is an irrefutable proof of the fact that he is descended
from tailed ancestors. In woman the tail is generally by
one vertebra longer than in man ; frequently five separate
vertebra can be clearly distinguished on the female rump ;
as a rule there are only four on the male rump. At earlier
stages of the embryo their number is even greater. There
also still exist rudimentary muscles in the human tail which

RUDIMENTARY ORGANS. 329

formerly moved it. The tailless human apes (gorilla, chim-
panzee, orang, gibbon) are in this respect exactly like man.
Another case of human rudimentary organs, only belong-
ing to the male, and which obtains in like manner in all male
mammals, is furnished by the mammary glands on the
breast, which, as a rule, are active only in the female sex.
However, cases of different mammals are known, especially
of men, sheep, and goats, in which the mammary glands
were fully developed in the male sex, and yielded milk as
food for their offspring. Humboldt came across a lonely
settler in a South American primaeval forest, whose wife
had died in child-bed. In his despair the man placed the
new-born infant to his own breast, and through the con-
tinued irritation which its repeated endeavours to suck
exercised upon his rudimentary mammary glands, their lost
activity was again restored to them. I have already
mentioned (p. 12) that the rudimentary auricular muscles
in man can still be employed to move their ears, by some
persons who have perseveringly practised them. In fact,
rudimentary organs are frequently very differently developed
in different individuals of the same species ; in some they
are tolerably large, in others very small. This circumstance
is very important for their explanation, as is also the other
circumstance that generally in embryos, or in a very early
period of life, they are much larger and stronger in propor-
tion to the rest of the body than they are in fully developed
and fully grown organisms. This can, in particular, be
easily pointed out in the rudimentary sexual organs of
plants (stamens and pistil), which I have already mentioned.
They are proportionately much larger in the young flower-
bud than in the mature flower.

330 THE HISTORY OP CREATION.

I have remarked (p. 15) that rudimentary or suppressed
organs were the strongest supports of the monistic or
mechanical conception of the universe. If its opponents,
the dualists and teleologists, understood the immense signifi-
cance of rudimentary organs, it would put them into a state
of despair. Their ludicrous attempts to explain that rudi-
mentary organs were given to organisms by the Creator " for
the sake of symmetry," or " as a formal provision," or " in
consideration of his general plan of creation," sufficiently
prove the utter impotence of their perverse conception of
the universe. I must here repeat that, even if we knew
absolutely nothing of the other phenomena of development,
we should be obliged to believe in the truth of the Theory of
Descent, solely on the ground of the existence of rudimentary
organs. Not one of its opponents has been able to throw
even a feeble glimmer of an acceptable explanation upon
these exceedingly remarkable and important phenomena.
There is scarcely any highly developed animal or vegetable
form which has not some rudimentary organs, and in most
cases it can be shown that they are the products of natural
selection, and that they have become suppressed by disuse.

The phenomena of retrogression or degeneration are
exactly the reverse of those of progression, which we observe
in the origin of new organs that arise from adaptation to
certain conditions of life, and by the use of parts as yet
incompletely developed. It is true our opponents usually
maintain that the origin of altogether new parts is com-
pletely inexplicable by the Theory of Descent. However, I
distinctly assert that to those who possess a knowledge of
comparative anatomy and physiology this matter does not
present the slightest difficulty. Every one who is familiar

GBOWTH OF NEW OKGANS. 331

with comparative anatomy and the history of development
will find as little difficulty about the origin of completely
new organs as about the utter disappearance of rudimentary
organs. The disappearance of the latter, viewed by itself, is
the converse of the origin of the former. Both processes
are particular phenomena of differentiation, which, like all
others, can be explained quite simply and mechanically by
the action of natural selection in the struggle for life.

When we closely examine the first appearance of new
organs, we as a rule observe nothing more than an increased
growth of one part of some already existing organ. But as
this part undertakes other functions, in accordance with the
laws of division of labour and the change of labour, a
separation soon becomes evident which leads to the gradual
development of the new organ, in accordance with the
theory of selection. This development is determined both
by the physiological laws of growth and nutrition, as also
happens in the reverse case, in that of retrogression in
rudimentary organs.

The infinite importance of the study of rudimentary
organs for the fundamental questions of natural philosophy
cannot be too highly estimated (see chap. xix. of my
" General Morphology," p. 266) ; we might set up with their
aid a theory of the unsuitability of parts in organisms,
as a counter-hypothesis to the old popular doctrine of the
suitability of parts. This latter dualistic teleology finally
leads us to supernatural dogmas and miracles, whereas we
obtain from the former, monistic dysteleology, a firm founda-
tion for our mechanical interpretation of nature ; it leads us,
by means of teleological mechanism, to pure Monism (see
Chap. XIV.).

332 THE HISTOBY OF CREATION.

CHAPTEK XIII.

THE INDIVIDUAL DEVELOPMENT OF ORGANISMS. THE
HISTORY OF THE DEVELOPMENT OF THE ANIMAL
TRIBES.

General Importance of Individual Development (Ontogeny). — Defects of
our Present Education. — Pacts in the Individual Development. — •
Agreement in the Individual Development of Man and the Verte-
brate Animals. — The Human Egg. — Fertilization. — Immortality. — The
Cleavage of the Egg. — Formation of Germ-layers. — Gastrulation. —
History of the Development of the Central Nervous System, of the
Extremities, of the Branchial Arches and of the Tail in Vertebrate
Animals. — Causal Connection between Ontogenesis and Phylogenesis. —
The Fundamental Law of Biogenesis. — Palingenesis or Recapitulative
Development. — Cenogenesis or Disordered Development. — Stages in
Comparative Anatomy. — Its Relation to the Palaeontologioal and
Embryological Series of Development.

The greater number of educated persons who nowadays
show more or less interest in our theories of development
unfortunately know next to nothing of the facts of organic
development from actual observation. Man, like other
mammals, appears at birth in an already developed form.
The chicken, like other birds, creeps out of the egg in a
completely developed form. But the wonderful processes
by which these completed animal forms arise are entirely
unknown to most persons. And yet these but little con-

ONTOGENY. 333

sidered processes contain a fund of knowledge, which is
unsurpassed by any other in general importance. For we
here have the development before our eyes as a tangible
fact, and we need only place a number of hen's eggs in an
incubator, and watch their development for three weeks
carefully with a microscope, in order to understand the
mystery by which a highly organized bird develops out of
a single simple cell. Step by step we can trace this
wonderful transformation, and step by step point out
how one organ is developed out of the other.

And for this reason alone — because, in fact, it is in this
domain only that the facts of development are presented to
us in tangible reality. I consider it of paramount conse-
quence to direct the reader's careful attention to those
infinitely important and interesting processes in the indi-
vidual development of organisms, viz. to ontogeny, and
above all to the ontogeny of the vertebrate animals, in-
cluding man. I wish specially to recommend these ex-
ceedingly remarkable and instructive phenomena to the
reader's most careful consideration; for, on the one hand,
they form one of our strongest supports for the theory of
descent, and for the monistic conception of the universe
generally; and, on the other hand, because hitherto it is
only a few privileged persons who have properly estimated
their immense general importance. These phenomena will
be found discussed very fully in my " Anthropogeny."

We cannot, indeed, but be astonished when we consider
the deep ignorance which still prevails, in the widest circles,
about the facts of the individual development of man and
organisms in general. These facts, the universal importance
of which cannot be estimated too highly, were established,

334 THE HISTOEY OF CEEATION.

in their most important outlines, even more than a hundred
years ago, in 1759, by the great German naturalist Caspar
Friedrich Wolff, in his classical " Theoria Generationis."
But, just as Lamarck's Theory of Descent, founded in 1809,
lay dormant for half a century, and was only awakened to
new and imperishable life in 1859, by Darwin, in like
manner Wolff's Theory of Epigenesis remained unknown for
nearly half a century ; and it was only after Oken, in 1806,
had published his history of the development of the in-
testinal tube, and after Meckel, in 1812, had translated
Wolff's work (written in Latin) on the same subject into
German, that Wolff's theory of epigenesis became more
generally known, and has since formed the foundation of
all subsequent investigations of the history of individual
development. The study of ontogenesis thus received a
great stimulus, and soon there appeared the classical in-
vestigations of the two friends, Christian Pander (1817)
and Carl Ernst Bar (1819). Bar, in his remarkable "Ent-
wickelungsgeschichte der Thiere," 20 worked out the ontogeny
of vertebrate animals in all its important facts. He carried
out a series of such excellent observations, and illustrated
them by such profound philosophical reflections, that his
work became the foundation for a thorough understanding
of this important group of animals, to which, of course,
man also belongs. The facts of embryology alone would
be sufficient to solve the question of man's position in
nature, which is the highest of all problems. Look atten-
tively at and compare the eight figures which are repre-
sented on the adjoining Plates II. and III., and it will be
seen that the philosophical importance of embryology cannot
be too highly estimated.

Germs or Embryos
Pi. II _ _ - .

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POPULAR IGNORANCE. 335

We may •well ask, What do our so-called "educated" circles,
who think so much of the high civilization of the nineteenth
century, know of these most important biological facts,
of these indispensable foundations for understanding their
own organization ? How much do our speculative philo-
sophers and theologians know about them, who fancy they
can arrive at an understanding of the human organism by
mere guesswork or divine inspiration ? What indeed do
the majority of naturalists, even so-called "zoologists" (in-
cluding the entomologists !), know about them ?

The answer to this question tells much to the shame of
the persons above indicated, and we must confess, willingly
or unwillingly, that these invaluable facts of human ontogeny
are, even at the present day, utterly unknown to most
people, or are in no way valued as they deserve to be. It
is in the face of such a condition of things as this that we
see clearly upon what a wrong and one-sided road the
much- vaunted culture of the nineteenth century still moves.
Ignorance and superstition are the foundations upon which
most men construct their conception of their own organiza-
tion, and its relation to the totality of things ; and the
palpable facts of the history of development, which might
throw the light of truth upon them, are wholly ignored.

The chief cause of this lamentable and mischievous state
of things is unquestionably owing to the education given in
our higher schools, and, above all, owing to our so-called
" classical education." For as it is still deeply imbued with
the scholasticism of the Middle Ages, it is still unable to
digest the enormous advances which natural science has
made in our century. It still does not consider that its
chief task should be to obtain a comprehensive knowledge of

336 THE HISTORY OF CREATION.

nature — of which we are ourselves a part — or of the present
state of the civilized world in which we live; its main
object is rather to acquire an accurate knowledge of the
history of the ancient countries, and, above all, a knowledge
of the Greek and Latin grammars. "We grant that a
thorough knowledge of classic antiquity is an exceedingly
important and indispensable part of our higher education ;
however, our pleasant acquaintance with antiquity we owe
in a much higher degree to painters and sculptors, to epic and
dramatic poets, than to classical philologists or to dreaded
grammarians. And to enjoy and understand these ancient
poets, it is as little necessary for us to read them in the
original text as it is for us to read the Bible in the original
Hebrew. The enormous expense of time and labour de-
manded by this luxurious sport in classical grammars might
be applied to infinitely better purpose, in the study of the
wonderful domain of phenomena which have been opened
up to us within the last half-century by the gigantic
advances of natural science, more especially of geology,
biology, and anthropology.

Unfortunately, however, the disparity between our daily
increasing knowledge of the real world, and the limited
standpoint of our so-called ideal education for the young,
is becoming greater day by day. A.nd it is, in fact, those
persons who exercise most influence upon our practical
education — the theologians and jurists — and likewise the
privileged teachers, the philologists and historians, who
know least about the most important phenomena of the
actually existing world, and of the real history of nature.
The structure and origin of our earth, as well as of our own
human body — subjects which have become of the utmost

SIMILARITY OF MAN'S AND DOG'S EMBRYO. 337

interest owing to the astonishing progress of modern
geology and anthropology — are unknown to the most of
them. To speak of the human egg and its development,
they consider either a ridiculous myth or a vulgar piece
of immodesty. And yet this subject reveals to us a series
of actually recognized facts, which cannot he surpassed in
general interest or high importance by any other in the
wide domain of human knowledge.

It is true these facts are not calculated to excite approval
among persons who assume a complete distinction between
man and the rest of nature, and who will not acknowledge
the animal origin of the human race. That origin must be
a very unpleasant truth to members of the ruling and
privileged castes in those nations among which there
exists an hereditary division of social classes, in consequence
of false ideas about the laws of inheritance. It is well
known that, even in our day, in many civilized countries
the idea of hereditary grades of rank goes so far that, for
example, the aristocracy imagine themselves to be of a
nature totally different from that of ordinary citizens, and
nobles who commit a disgraceful offence are punished by
being expelled from the caste of nobles, and thrust down
among the pariahs of "vulgar citizens." What are these
nobles to think of the blue blood in their privileged veins,
when they learn that all human embryos, those of nobles as
well as commoners, are scarcely distinguishable from the
tailed embryos of dogs and other mammals during the first
two months of development ?

As the object of these pages is solely to further the
general knowledge of natural truths, and to spread, in wider
circles, a natural conception of the relations of man to the

vol. I. z

338 THE HISTORY OF CREATION.

rest of nature, I shall be justified if I do not pay any
regard to the widely spread prejudice in favour of an ex-
ceptional and privileged position for man in creation, and
simply give here the embryological facts from which the
reader will be able to draw conclusions affirming the
groundlessness of those prejudices. I wish all the more
to entreat my readers to reflect carefully upon these facts of
ontogeny, as it is my firm conviction that a general know-
ledge of them can only promote the intellectual advance,
and thereby the mental perfecting, of the human race.

Amidst all the infinitely rich and interesting material
which lies before us in the ontogeny of vertebrate animals,
that is, in the history of their individual development, I shall
here confine myself to showing some of those facts which
are of the greatest importance to the Theory of Descent in
general, as well as in its special application to man. Man
is at the beginning of his individual existence a simple egg,
a single little cell, just the same as every animal organism
which originates by sexual generation. The human egg is
essentially the same as that of all other mammals, and can-
not be distinguished from the egg of the higher mammals.
The egg represented in Fig. 5 might be that of a man or an
ape as well as of a dog, a horse, or any other mammal. Not
only the form and structure, but even the size of the egg in
most mammals is the same as in man, namely, about the
120th part of an inch in diameter, so that the egg under
favourable circumstances, with the naked eye, can just be
perceived as a small speck. The differences which really
exist between the eggs of different mammals and that of
man do not consist in the form, but in the chemical mixture,
in the molecular composition of the albuminous combination

THE HUMAN EGG. 339

of carbon, of which the egg essentially consists. These
minute individual differences of all eggs, and particularly
the molecular structure of the kernel, depend probably upon
indirect or potential adaptation (and especially upon the
law of individual adaptation) ; they are, indeed, not directly
perceptible to the exceedingly imperfect senses of man, but
are cognizable through well-founded indirect inferences, as
the primary causes of the difference of all individuals.

The human egg is, like that of all other mammals, a
small globular bladder, which contains all the constituent
parts of a simple organic cell (Fig. 5). The most essential

Pis. 5. — The human egg a hundred times en-
larged, a. The kernel-speck, or nucleolus (the
so-called germinal spot of the egg). I. Kernel,
or nucleus (the so-called germinal vesicle of the
egg) . c. Cell-substance, or protoplasm (so-called
yolk of the egg), d. Cell-membrane (the yolk-
membrane of the egg; in mammals, on account
of its transparency, called zona pellucida). The
eggs of other mammals are of the same form.

parts of it are the mucous cell-substance, or the protoplasma
(c), which in an egg is called the " yolk," and the cell-kernel,
or nucleus (b), surrounded by it, which is here called by the
special name of the "germinal vesicle." The latter is a
delicate, clear, glassy globule of albumen, of about l-600th
part of an inch in diameter, and surrounds a still smaller,
sharply marked, rounded granule (a), the kernel-speck, or
the nucleolus of the cell (in the egg it is called the " germinal
spot "). The outside of the globular egg-cell of a mammal
is surrounded by a thick pellucid membrane, the cell-mem-
brane or yolk-membrane, which here bears the special
name of zona pellucida (d). The eggs of many lower
animals (for example, of many Medusae) differ from this in

340 THE HISTOEY OF CREATION.

being naked cells, as the outer covering, or cell-membrane,
is wanting.

As soon as the egg (ovulum) of the mammal has attained
its full maturity, it leaves the ovary of the female, in which
it originates, and passes into the oviduct, and through this
narrow passage into the wider pouch or womb (uterus). If,
meanwhile, the egg is fructified by the male seed (sperm),
it develops itself in this pouch into an embryo, and does
not leave it until perfectly developed and capable of coming
into the world at birth as a young mammal.

The process of fertilization, which was formerly consi-
dered one of the most mysterious and wonderful phenomena,
has become perfectly clear and intelligible to us owing to
the great advances of our scientific knowledge during the
last ten years, and these we owe, above all, to the admirable
investigations made by the brothers Oscar and Richard
Hertwig, Edward Strasburger, Biitschli, and many others.
We now know that the fertilization of the egg, as the
most essential process in sexual propagation, is nothing
further than a commingling of two different cells, the
paternal sperm-cell and the maternal egg-cell. Of the
thousands of agile little whip-cells which are contained
in a drop of the male seminal fluid, a single one penetrates
into the female egg- cell, and becomes completely mixed
with it. And in this commingling of the two sexual cells,
the main process is the copulation of the two cell-kernels.
The male sperm-nucleus commingles with the female egg-
nucleus, and this gives rise to the new progeny-nucleus,
the nucleus of the new progeny-cell (Cytula).

Twenty-three years ago, in my " General Morphology "
(vol. i. p. 288), I defined the importance of the two active

IMMORTALITY. 34I

parts of the cell thus : " The inner nucleus has to attend to
the transmission of hereditary characteristics, the outer
plasma (or Cytoplasma) to the adaptation to the relations
of the outer world." This proposition has been fully con-
firmed by the numerous careful investigations of recent
times. The male sperm-nucleus, in the process of fertili-
zation, transmits the hereditary qualities of the father,
whereas the female egg-nucleus attends to the transmission
of the peculiarities of the mother.

The progeny-cell (Oytula), or the so-called "fertilized
egg-cell " (and often wrongly called the " first cell of the
cleavage "), is, accordingly, an entirely new creature. For
as its substance is a material product of the commingling of
the paternal seed-cell with the maternal egg-cell, the vital
qualities inseparably connected with these are a mixture
of the physiological peculiarities of both parents. The
individual mixture of character which every child inherits
from both parents must be traced back to the commingling
of the two cellular substances at the moment of fructifica-
tion. And it is at this important moment, moreover, that
the existence of the individual begins, and not at the time
of actual birth, which in man does not take place till nine
months afterwards.

The general importance of these extremely interesting
processes has hitherto not been estimated at all in the
measure which it deserves to be. To point to but one of
the most important deductions from it, it throws quite a
new light upon the weighty question as to immortality.
The doctrine of the 'personal immortality of man has, indeed,
been absolutely refuted for more than half a century by the
great progress in our knowledge of comparative physiology

342 THE HISTOBY OF CEEATION.

and ontogeny, of comparative psychology and psychiatry.
But still there might nevertheless have existed some doubts
as to whether some part, at least, of our mental life might
not be independent of the brain, and traceable to the activity
of an immaterial soul. However, since we have been able
accurately to follow the process of fertilization, since we
know that even the finest qualities of mind in both parents
are transmitted to the child by the act of fertilization,
and that this inheritance is determined simply by the com-
mingling of the two copulating cell-kernels, all the doubts
referred to above have vanished. It must appear utterly
senseless now to speak of the immortality of the human
person, when we know that this person, with all its indi-
vidual qualities of body and mind, has arisen from the act
of fertilization, hence that it has a final beginning to its
existence. How can this person possess an eternal life
without an end ? The human person, like every other
many-celled individual, is but a passing phenomenon of
organic life. With its death the series of its vital activities
ceases entirely, just as it began with the act of fertilization.
The variations of form and transformations which the
fertilized egg must go through within the uterus before it
assumes the form of the mammal are exceedingly remark-
able, and proceed from the beginning in man precisely in
the same way as in other mammals. At first the fructi-
fied egg of the mammal acts as a single-celled organism,
which is about to propagate independently and increase
itself; for example, an Amceba (compare Fig. 2, p. 193). In
point of fact, the simple egg-cell becomes two cells by the
process of cell-division which I have already described
(Fig. 6 A).

THE CLEAVAGE OF THE YOLK. 343

The same process of cell-division now repeats itself
several times in succession. In this way, from two cells
(Fig. 6 .4) there arise four (Fig. 6 B); from four, eight
(Fig. 6 G); from eight, sixteen; from these, thirty-two, etc.

Fig. 6. — First commencement of the development of a mammal's egg, the
so-called " yolk-cleavage " (propagation of the egg-cell by repeated self -
division) . A. The egg, by the formation of the first furrow, falls into two
cells. B. These by division fall into four cells. 0. These latter have fallen
into eight cells. D. By continued division a globular mass of numerous
cells has arisen, the Morula.

Each time the division of the cell-kernel or nucleus precedes
that of the cell-substance, or protoplasma. As the division
of the latter always commences with the formation of a
superficial annular furrow, or cleft, the whole process is
usually called the furrowing of the egg, or yolk- cleavage,
and the products of it, that is, the cells arising from the con-
tinued halving, are called the cleavage spheres (Blastomera).
However, the whole process is nothing more than a simple,
oft-repeated division of cells, and the products of it are
actual, naked cells. Finally, through the continued division
or " furrowing " of the mammal's egg, there arises a mulberry-
shaped ball (Morula), which is composed of a great number
of small spheres, naked cells, containing kernels (Fig. 6 D).
These cells are the materials out of which the body of the
young mammal is constructed. Every one of us has once

344 THE HISTORY OF CREATION.

been such a simple mulberry-shaped ball, composed only of
small cells.

The further development of the globular lump of cells,
which now represents the young body of the mammal, con-
sists first in its changing into a globular bladder, as fluid
accumulates within it. This bladder is called the germ-
bladder (Blastula or Vesicula blastodermica). Its wall is
at first composed merely of homogeneous cells. But soon,
at one point on the wall, arises a disc-shaped thickening, as
the cells here increase rapidly, and this thickening is
now the foundation of the actual body of the germ or
embyro, while the other parts of the germ-bladder serve
only for its nutrition. The thickened disc, or foundation
of the embryo, soon assumes an oblong, and then a fiddle-
shaped form, in consequence of its right and left walls
becoming convex (Fig. 7, p. 349). At this stage of develop-
ment, in the first form of their germ or embryo, not only all
mammals, including man, but even all vertebrate animals
in general — birds, reptiles, amphibious animals, and fishes
— can either not be distinguished from one another at all,
or only by very unessential differences, such as size and
the arrangement of the egg-coverings. In every one the
entire body consists of nothing but two thin layers of simple
cells ; these lie one on the top of the other, and are therefore
called the primary germ-layers. The outer or upper germ-
layer is the skin-membrane (exoderm), the inner or lower
the intestinal membrane (entoderm).

The germinal form of the animal body, which thus consists
merely of the two primary germ-layers, is the same in all of
the many-celled animals (Metazoa), and hence is of the
utmost importance. I was the first to maintain the general

Development of the Gastrula.

THE GASTBULA. 345

application of this two-leafed germinal form to all the
Metazoa, and consequently of the "homology of the two
primary germ-leaves," and did so in 1872 in my "Monograph
of the Calcareous Sponges ;" and detailed proofs of this were
given in my "Studies on the Gastrsea Theory." And as
this very important germinal form, in its original pure
shape (Plate V., Fig. 8, 18 ; Plate XII., Fig. A 4, B 4),
resembles a double-walled goblet, I called it goblet-germ
(Gastrula), and the process of its formation gastrvlation. I
shall discuss it more fully later on in my twentieth chapter.
Even in 1872 I concluded, from the remarkable agreement
of the Gastrula in all many-celled animals, that all of the
metazoa (according to fundamental law of biogenesis) must
have been originally derived from a single common primary
form ; and this hypothetical primary form is the Gastroea,
in all essential points the same as the goblet-shaped
Gastrula.

The gastrula of mammals, like that of many of the other
higher animals — in consequence of the peculiar conditions
under which it develops — has lost its original goblet-shape
and has assumed the disc-shape already described. How-
ever, this disc-shape (Discogastrula) is only a secondary
modification of the goblet-germ. As in the latter case, here
also the two primary germ-layers divide subsequently into
the four secondary germ-layers. And these consist of
absolutely nothing but homogeneous cells ; yet every single
one has a different significance in the construction of the
body of the vertebrate animal. Out of the upper or outer
germ-layer arises only the outer skin (epidermis), together
with the central parts of the nervous system (spinal marrow
and brain) ; out of the lower or inner layer arises only

346 THE HISTORY OF CREATION.

the inner delicate skin (epithelium) which lines the whole
intestinal tube from the mouth to the anus, together with
all the glands connected with it (lung, liver, salivary
glands, etc.) ; out of the middle germ-layer lying between
the two others arise all the other organs, muscles, bones,
blood-vessels. (Compare my " Anthropogeny," and my
"Studies on the Gastrsea Theory," for the processes of
the individual development of man and the animals.)

Now, the processes by which the various and exceedingly
complicated parts of the fully-formed body of vertebrate
animals arise out of such simple material — out of the three
germ-layers composed only of cells — are, in the first place,
the repeated division, and consequently the increase of cells ;
in the second place, the division of labour or differentiation
of these cells; and thirdly, the union of the variously
developed or differentiated cells, for the formation of the
different organs. Thus arises the gradual progress or per-
fecting which can be traced step bj 7 step in the development
of the embryonic body. The simple embryonic cells, which
are to constitute the body of the vertebrate animal, stand
in the same relation to each other as citizens who wish to
found a state. Some take to one occupation, others to
another,. and work together for the good of the whole. By
this division of labour, or differentiation, and the perfecting
(the organic progress) which is connected with it, it becomes
possible for the whole state to accomplish undertakings
which would have been impossible to the single individual.
The whole body of the vertebrate animal, like every
other many-celled organism, is a republican state of
cells, and consequently it can accomplish organic func-
tions which the individual cell, as a solitary individual (for

CELLS AS CITIZENS. 347

example, an Amoeba, or a single-celled plant), could never
perform.

No sensible person supposes that carefully devised insti-
tutions, 'which have been established for the good of the
whole, as well as for the individual, in every human state,
are the results of the action of a personal and supernatural
Creator, acting for a definite purpose. On the contrary,
every one knows that these useful institutions of organiza-
tion in the state are the consequences of the co-operation
of the individual citizens and their common government,
as well as of adaptation to the conditions of existence of
the outer world. Just in the same way we must judge of the
many-celled organism. In it also all the useful arrangements
are solely the natural and necessary result of the co-operation,
differentiation, and perfecting of the individual citizens —
the cells — and by no means the artificial arrangements of a
Creator acting for a definite purpose. If we rightly consider
this comparison, and pursue it further, we can distinctly
see the perversity of that dualistic conception of nature
which discovers the action of a creative plan of construction
in the various adaptations of the organization of living
things.

Let us pursue the individual development of the verte-
brate animal body a few stages further, and see what is next
done by the citizens of this embryonic organism. In the
central line of the violin-shaped disc, which is composed of
the three cellular germ-layers, there arises a straight deli-
cate furrow, the so-called " primitive streak," by which the
violin-shaped body is divided into two equal lateral halves —
a right and a left part or " antimer." On both sides of that
streak or furrow, the upper or external germ-layer rises in

348 THE HISTOEY OF CBEATION.

the form of a longitudinal fold, and both folds then grow-
together over the furrow in the central line, and thus form
a cylindrical tube. This tube is called the marrow-tube, or
medullary canal, because it is the foundation of the central
nervous system, the spinal marrow (medulla spinalis). At
first it is pointed both in front and behind, and it remains
so for life in the lowest vertebrate animal, the brainless,
skull-less Lancelet (Amphioxus). But in all other vertebrate
animals, which we distinguish from the latter as skulled
animals, or Craniota, a difference between the fore and
hinder end of the marrow-tube soon becomes visible, the
fore end becoming dilated, and changing into a roundish
bladder, the foundation of the brain.

In all Craniota, that is, in all vertebrate animals possess-
ing skull and brain, the brain, which is at first only the
bladder-shaped dilatation of the anterior end of the spinal
marrow, divides into five bladders lying one behind the
other, four superficial, transverse in-nippings being formed.
These five brain-bladders, out of which afterwards arise all
the different parts of the intricately constructed brain, can
be seen in their original condition in the embryo represented
in Fig. 7. It is just the same whether we examine the em-
bryo of a dog, a fowl, a lizard, or any other higher vertebrate
animal. For the embryos of the different skulled animals
(at least the three higher classes of them, the reptiles, birds,
and mammals) cannot be in any way distinguished at the
stage represented in Fig. 7. The whole form of the body is
as yet exceedingly simple, being merely a thin, leaf-like disc.
Face, legs, intestines, etc., are as yet completely wanting.
But the five bladders are already quite distinct from one
another.

DEVELOPMENT OF THE BRAIN.

349

Fig. 7. — Embryo of a mammal or bird, in
which the five brain-bladders have just com-
menced to develop, v. Fore brain, z. Twixt brain.
m. Mid brain, h. Hind brain, n. After brain.
p. Spinal marrow, a. Eye-bladders, w. Primi-
tive vertebrae, d. Spinal axis or notochord.

The first bladder, the fore brain,
is in so far the most important that
it principally forms the larger hemi-
spheres of the so-called larger brain
(cerebrum), that part which is the
seat of the higher mental activities.
The more these activities are de-
veloped in the series of vertebrate
animals, the more do the two lateral
halves of the fore brain, or the larger
hemispheres, grow at the expense of
the other bladders, and overlap them
in front and from above. In man, where they are most
strongly developed, agreeing with his higher mental activity,
they eventually almost entirely cover the other parts from
above (compare Plates II. and III.). The second bladder,
the twixt brain (z), forms that portion of the brain which
is called the centre of sight, and stands in the closest relation
to the eyes (a), which grow right and left out of the fore
brain in the shape of two bladders, and later lie at the
bottom of the twixt brain. The third bladder, the mid
brain (m), for the most part vanishes in the formation of
the so-called four bulbs, a bossy portion of the brain, which
is strongly developed in reptiles and birds (Fig. E, F, Plate
II.), whereas in mammals it recedes much more (Fig. 0, H,

350 THE HISTORY OF CREATION.

Plate III.). The fourth bladder, the hind brain (h), forms
the so-called little hemispheres, together with the middle
part of the small brain (cerebellum), a part of the brain as
to the function of which the most contradictory conjectures
are entertained, but which seems principally to regulate
the co-ordination of movements. Lastly, the fifth bladder,
the after brain (n), develops into that very important part
of the central nervous system which is called the prolonged
narrow (medulla oblongata). It is the central organ of the
respiratory movements, and of other important functions,
and an injury to it immediately eauses death, whereas the
large hemispheres of the fore brain (or the organ of the
" soul," in a restricted sense) can be removed bit by bit, and
even completely destroyed, without causing the death of
the vertebrate animal — only its higher mental activities
disappearing in consequence.

These five brain-bladders, in all vertebrate animals which
possess a brain at all, are originally arranged in the same
manner and develop gradually in the different groups so
differently, that it is afterwards very difficult to recognize
the corresponding parts in the fully developed brains. In
the early stage of development which is represented in
Fig. 7, it seems as yet quite impossible to distinguish the
embryos of the different mammals, birds, and reptiles from
one another. But if we compare the much more developed
embryos on Plates II. and III. with one another, we can
clearly see an inequality in their development, and espe-
cially it will be perceived that the brain of the two mammals
(Gr and if) already strongly differ from that of birds (F) and
of reptiles (E). In the two latter the mid brain predomi-
nates, but in the former the fore brain Even at this stage

VERTEBRATE DEVELOPMENT. 351

the brain of the bird (F) is scarcely distinguishable from
that of the tortoise (E), and in like manner the brain of the
dog (G) is as yet almost the same as that of man (H). If,
on the other hand, we compare the brains of these four
vertebrate animals in a fully developed condition, we find
them so very different in all anatomical particulars, that we
cannot doubt for a moment as to which animal each brain
belongs.

I have here explained the original equality, the gradual
commencement, and the ever-increasing separation or
differentiation of the embryos in the different vertebrate
animals, taking the brain as a special example, just because
this organ of the soul's activity is of special interest. But
I might as well have discussed in its stead the heart, or the
liver, or the limbs, in short, any other part of the body,
since the same wonder of creation is here ever repeated,
namely, that all parts are originally the same in the different
vertebrate animals, and that the variations by which the
different classes, orders, families, genera, etc., differ and
deviate from one another, are only gradually developed.
In my work on the "History of the Individual Develop-
ment of Man," you will find the proof of this for every
separate organ.

There are certainly few parts of the body which are so
differently constructed as the limbs or extremities of the
vertebrate animals*. Now, I wish the reader to compare, in
Fig. A — H on Plates II. and III., the four extremities (bv)
of the embryos with one another, and he will scarcely be
able to perceive any important differences between the
human arm (H bv), the wing of a bird (F bv), the slim fore
leg of a dog (G bv), and the plump fore leg of the tortoise

352 THE HISTORY OF CREATION.

(E bv). In comparing the hinder extremities (b h) in these
figures he will find it equally difficult to distinguish the leg
of a man (H bh), of a bird (F bh), the hind leg of a dog
(G bh), and that of a tortoise (F bh). The fore as well as
the hinder extremities are as yet short, broad lumps, at the
ends of which the foundations of the five toes are placed,
connected as yet by a membrane. At a still earlier stage
(Fig. A — D) the five toes are not marked out at all, and it is
quite impossible to distinguish even the fore and hinder
extremities from one another. The latter, as well as the
former, are nothing but simple roundish processes, which
have grown out of the side of the trunk. At the very early
stage represented in Fig. 7 they are completely wanting,
and the whole embryo is a simple trunk without a trace
of limbs. (Compare also Plate IV. and my explanation of
it in the Appendix.)

I wish especially to draw attention in Plates II. and
III., which represent embryos in early stages of develop-
ment (Fig. A — D) — and in which we are not able to recog-
nize a trace of the full-grown animal — to an exceedingly
important formation, which originally is common to all
vertebrate animals, but which at a later period is trans-
formed into the most different organs. Every one surely
knows the gill-arches of fish, those arched bones which
lie behind one another, to the number of three or four,
on each side of the neck, and which support the gills,
the respiratory organs of the fish (double rows of red leaves,
which are popularly called " fishes' ears "). Now, these gill-
arches originally exist exactly the same in man (D), in dogs
(G), in fowls (B), and in tortoises (A), as well as in all other
vertebrate animals. (In Fig. J. — D the three gill-arches of

THE HUMAN TAIL. 353

the right side of the neck are marked Tc t hi k s .) Now, it is
only in fishes that these remain in their original form, and
develop into respiratory organs. In the other vertebrate
animals they are partly employed in the formation of the
face (especially the jaw apparatus), and partly in the forma-
tion of the organ of hearing.

Finally, when comparing the embryos on Plates II. and
III., we must not fail to give attention again to the human
tail (s), an organ which, in the original condition, man
shares with all other vertebrate animals. The discovery of
tailed men was long anxiously expected by many monistic
philosophers, in order to establish a closer relationship
between man and the other mammals. And in like manner
their dualistic opponents often maintained with pride that
the complete want of a tail formed one of the most important
bodily distinctions between men and animals, though they
did not bear in mind the many tailless animals which really
exist. Now, man in the first months of development pos-
sesses a real tail as well as his nearest kindred, the tailless
apes (orang-outang, chimpanzee, gorilla), and vertebrate
animals in general. But whereas, in most of them — for
example, the dog (C, 6) — in the course of development it
always grows longer, in man (Fig. D, H) and in tailless
mammals, at a certain period of development, it degenerates
and finally completely disappears. However, even in fully
developed men, the remnant of the tail is seen in the three,
four, or five tail vertebrae (vertebras coccygese) as an aborted
or rudimentary organ, which forms the hinder or lower end
of the vertebral column, an infallible proof of our derivation
from tailed ancestors.

Most persons even now refuse to acknowledge the most
vol. 1. 2 a

354 THE HISTORY OF CREATION.

important deduction of the Theory of Descent, that is, the
palseontological development of man from ape-like, and
through them from still lower, mammals, and consider such
a transformation of organic form as impossible. But, I ask,
are the phenomena of the individual development of man,
the fundamental features of which I have here given, in any
way less wonderful? Is it not in the highest degree re-
markable that all vertebrate animals of the most different
classes — fishes, amphibious animals, reptiles, birds, and
mammals — in the first periods of their embryonic develop-
ment cannot be distinguished at all, and even much later,
at a time when reptiles and birds are already distinctly
different from mammals, that the dog and the man are
almost identical ? Verily, if we compare those two series of
development with one another, and ask ourselves which of
the two is the more wonderful, it must be confessed that
ontogeny, or the short and quick history of development of
the individual, is much more mysterious than phylogeny, or
the long and slow history of development of the tribe. For
one and the same grand change of form is accomplished by
the latter in the course of many thousands of years, and by
the former in the course of a few months. Evidently this
most rapid and astonishing transformation of the individual
in ontogenesis, which we can actually point out at any
moment by direct observation, is in itself much more
wonderful and astonishing than the corresponding, but
much slower and gradual transformation which the long
chain of ancestors of the same individual has gone through
in phylogenesis.

The two series of organic development, the ontogenesis of
the individual and the phylogenesis of the tribe to which

EMBRYONIC RECAPITULATION. 355

it belongs, stand in the closest causal connection with each
other. I have endeavoured, in the second volume of the
'' General Morphology," 4 to establish this theory in detail,
as I consider it exceedingly important, and in my " Anthro-
pogenesis" have discussed the subject with regard to man.
As I have there shown, ontogenesis, or the development of
the individual, is a short and quick repetition (recapitula-
tion) of phylogenesis, or the development of the tribe to
which it belongs, determined by the laws of inheritance and
adaptation ; by tribe I mean the ancestors which form the
chain of progenitors of the individual concerned. (Compare
my " Studies on the Gastraea Theory," 1877, p. 70.)

The agreement between many of the germinal forms of
the higher animals and the developed forms of kindred
lower animals is so striking that they were observed even
by the earlier naturalists. Oken, Treviranus, and others
drew attention to them as early as the beginning of our
century. Meckel, in 1821, spoke of a " resemblance between
the development of the embryo and the animal tribe." In
1828 Bar critically discussed the question, how far within
a type or tribe (for instance, the vertebrates) the germinal
forms of the higher animals pass through the permanent
forms of the lower. However, there could, of course, be no
actual understanding of this wonderful resemblance as long
as the theory of descent had not become recognized. When
Darwin, in 1859, at last accomplished this, he also, in his
fourteenth chapter of his chief work, briefly referred to the
great importance of the embryonic evidence. Still Fritz
Miiller was the first to discuss the subject fully and clearly,
which he did in connection with the Crustacea in his admir-
able work " On Darwin." I have myself given Miiller's

356 THE HISTOEY OF CBEATION.

theory a more definite form in my " biogenetic fundamental
law," and worked it out further both in my " Study of the
Gastrsea Theory" and in my " Anthropogenesis." This
fundamental proposition is the most important general law
of organic development, the fundamental biogenetic law.

In this intimate connection of ontogeny and phylogeny,
I see one of the most important and irrefutable proofs of the
Theory of Descent. No one can explain these phenomena
unless he has recourse to the laws of Inheritance and
Adaptation ; by these alone are they explicable. And the
laws, which we have previously explained, as the laws of
abbreviated, of homochronic, and of homotopic inheritance,
here deserve renewed consideration. As so high and com-
plicated an organism as that of man, or the organism of
any other mammal, rises upwards from a simple cellular
state, and progresses in its differentiation and perfecting, it
passes through the same series of transformations which its
animal progenitors have passed through, during immense
spaces of time, inconceivable ages ago. I have already
pointed out this extremely important parallelism of the
development of individuals and tribes (p. 10). Certain
very early and low stages in the development of man, and
the other vertebrate animals in general, correspond com-
pletely in many points of structure with conditions which
last for life in the lower fishes. The next phase presents
us with a change of the fish-like being into a kind of
amphibious animal At a later period the mammal, with
its special characteristics, develops out of the amphibian,
and we can clearly see, in the successive stages of its later
development, a series of steps of progressive transformation
which evidently correspond with the differences of different

EMBRYONIC ADAPTATIONS. 357

mammalian orders and families. Now, it is precisely in
the same succession that we also see the ancestors of man,
and of the higher mammals, appear one after the other in
the earth's history ; first fishes, then amphibians, later the
lower, and at last the higher mammals. Here, therefore,
the embryonic development of the individual is completely
parallel to the palseontological development of the whole
tribe to which it belongs, and this exceedingly interesting
and important phenomenon can be explained only by the
interaction of the laws of Inheritance and Adaptation.

And, indeed, in order properly to understand and to apply
the biogenetic fundamental law, it must be remembered
that the hereditary repetition of the original chain of
primary forms is but seldom (or, strictly speaking, never !)
perfectly complete in the corresponding and parallel chain
of embryonic forms. For the changing conditions of
existence exercise their influence upon every single em-
bryonic form as well as upon the fully developed organism.
Besides, the law of abridged inheritance constantly
endeavours to effect a simplification of the original process
of development. On the other hand, however, the embryo
may, by its adaptation to new conditions of life (e.g. by
the development of protecting coverings), acquire new forms,
which were wanting in the original figure of the primary
form that had been transmitted to it by inheritance. Hence
the figure of the embryo must necessarily (especially in its
later stages of development) deviate more or less from the
original figure of the corresponding primary form, and,
indeed, the more so the more highly developed the
organism is.

Accordingly, all the phenomena of the embryonic or

358 THE HISTOEY OF CREATION.

individual development (Ontogenesis) may in reality fall
into two different groups. The first group comprises the
primasval development or the recapitulative development
(Palingenesis), and exhibits still all those primaeval con-
ditions which have been transmitted by inheritance from
the primary forms (thus, for instance, in the human embryo,
the gill-arches, the chorda, the tail, etc.). The second group,
on the other hand, contains the disturbed or falsified
development (Oenogenesis), and obscures the original figure
of the individual development by the introduction of new
and foreign shapes, which did not exist in the earlier forms,
and were acquired by the embryo only by adaptation to the
peculiar conditions of the individual development (thus, for
instance, in the human embryo, the egg-coverings, the yelk-
sack, the placenta, etc.).

Every critical investigation and estimation of the indi-
vidual development has, therefore, first of all to distinguish
how many of the embryonic facts are palingenetic docu-
ments (pertaining to the recapitulative development), and
how many, on the other hand, are oenogenetic variations of
those documents (pertaining to the disturbed history). The
more that the original palingenesis is retained in the
embryonic development of every organism by inheritance,
the more faithful will be the picture it gives us of the
history of its original development ; but, on the other hand,
the more that cenogenesis has influenced the germinal
forms by adaptation, the more the primary image will be
obliterated or altered.

The important parallelism of the palaeontological and of
the individual developmental series now directs our atten-
tion to a third developmental series, which stands in the

COMPARATIVE ANATOMY. 359

closest relations to these two, and which likewise runs, on
the whole, parallel to them. I mean that series of develop-
ment of forms which constitutes the object of investigation
in comparative anatomy, and which I will briefly call the
systematic developmental series of species. By this we
understand the chain of the different, but related and con-
nected forms, which exist side by side at any one period of
the earth's history ; as, for example, at the present moment.
While comparative anatomy compares the different forms
of fully developed organisms with one another, it endeavours
to discover the common prototypes which underlie, as it
were, the manifold forms of kindred species, genera, classes,
etc., and which are more or less concealed by their particular
differentiation. It endeavours to make out the series of
progressive steps which are indicated in the different
degrees of perfection of the divergent branches of the tribe.
In fact, to keep to the illustration already employed,
comparative anatomy shows us how the individual organs
and systems of organs in the tribe of vertebrate animals —
in the different classes, families, and species of it — have
unequally developed, differentiated, and perfected them-
selves. It shows us how far the succession of classes of
vertebrate animals, from the Fishes upwards, through
the Amphibia to the Mammals, and here again from the
lower to the higher orders of Mammals, forms a progressive
series or ladder. What light is thrown upon the subject by
the knowledge of this progressive development of the organs,
may be gathered from the works of the great comparative
anatomists of all ages — in the works of Goethe, Meckel,
Cuvier, Johannes Mtiller, Gregenbaur, and Huxley.

The developmental series of mature forms, which com-

360 THE HISTORY OF CREATIOX.

parative anatomy points out in the different diverging and
ascending steps of the organic system, and which we call
the systematic developmental series, corresponds with one
portion of the palaeontological developmental series; it deals
with the anatomical result of the latter in the present ; and
is, at the same time, parallel with the individual develop-
mental series ; and this, again, is parallel with the palseon-
tological series.

The varied differentiation, and the unequal degree of
perfecting which comparative anatomy points out in the
developmental series of the system, is chiefly determined
by the ever-increasing variety of conditions of existence to
which the different groups adapt themselves in the struggle
for life, and by the different degrees of rapidity and com-
pleteness with which this adaptation has been effected.
Conservative groups which have retained their inherited
peculiarities most tenaciously remain, in consequence, at the
lowest and rudest stage of development. Those groups pro-
gressing most rapidly and variously, and which have adapted
themselves to changed conditions of existence most readily,
have attained the highest degree of perfection. The
further the organic world developed in the course of the
earth's history, the greater must the gap between the lower
conservative and the higher progressive groups have be-
come, as in fact may be seen too in the history of nations. In
this way also is explained the historical fact, that the most
perfect animal and vegetable groups have developed them-
selves in a comparatively short time to a considerable height,
while the lowest or most conservative groups have remained
stationary throughout all ages in their original simple stage,
or have progressed, but very slowly and gradually.

THE THREE SERIES PARALLEL. 361

The series of man's progenitors clearly shows this state
of things. The sharks of the present day are still very like
the primary fish, which are among the most ancient verte-
brate progenitors of man, and the lowest amphibians of the
present day (the gilled salamanders and salamanders) are
very like the amphibians which first developed themselves
out of fishes. So, too, the later ancestors of man, the
Monotremata and Marsupials, the most ancient mammals,
are at the same time the most imperfect animals of the class
which still exist. The laws of inheritance and adaptation
known to us are completely sufficient to explain this ex-
ceedingly important and interesting phenomenon, which may
be briefly designated as the parallelism, of individual, of
palceontological, and of systematic development, and of their
respective progress and differentiation. No opponent of the
Theory of Descent has been able to give an explanation
of this extremely wonderful fact, whereas it is perfectly
explained, according to the Theory of Descent, by the laws
of Inheritance and Adaptation.

If we examine this parallelism of the three organic
series of development more accurately, we have to add
the following special distinctions. Ontogeny, or the history
of the individual development of every organism (embryology
and metamorphology), presents us with a simple unbranch-
ing or graduated chain of forms ; and so it is with that
portion of phytogeny which comprises the palseontological
history of development of the direct ancestors of every
individual organism. But the whole of phylogeny — which
meets us in the natural system of every organic tribe or
phylum, and which is concerned with the investigation
of the palseontological development of all the branches of

362 THE HISTORY OF CREATION.

this tribe — forms a branching or tree-shaped developmental
series, a veritable pedigree. If we examine and compare
the branches of this pedigree, and place them together
according to the degree of their differentiation and per-
fection, we obtain the tree-shaped, branching, systematic
developmental series of comparative anatomy. Strictly
speaking, therefore, the latter is parallel only to a portion
of the whole of phytogeny, and consequently only partially
parallel to ontogeny ; for ontogeny itself is parallel only to
a portion of phylogeny.

Of late years it has been a much-disputed point which of
the three great series of development is of most importance
to transformism and for our knowledge of the primary rela-
tionships. This dispute is superfluous ; for, as a rule, all
three are of equal value ; in individual cases, however, the
phylogenetic investigator will have to examine every
special case critically to ascertain whether he is to set
greater value on the facts of palaeontology, of ontogeny, or
of comparative anatomy.

All the phenomena of organic development above dis-
cussed, especially the threefold genealogical parallelism,
and the laws of differentiation and progress, which are
evident in each of these three series of organic development,
are exceedingly important proofs of the truth of the Theory
of Descent. For by it alone can they be explained, whereas
its opponents cannot even offer a shadow of an explanation
of them. Without the Doctrine of Filiation, the fact of
organic development in general cannot be understood. We
should, therefore, for this reason alone, be forced to accept
Lamarck's Theory of Descent, even if we did not possess
Darwin's Theory of Selection.

( 363 )

CHAPTER XIV.

MIGRATION AND DISTRIBUTION OP ORGANISMS.
CHOEOLOGY AND THE ICE PERIOD OP THE EARTH.

Chorological Facts and Causes. — Origin of most Species in one Single
Locality : " Centres of Creation." — Distribution by Migration. — Active
and Passive Migrations of Animals and Plants. — Plying Animals. —
Analogies between Birds and Insects. — Bats. — Means of Transport. —
Transport of Germs by Water and by Wind. — Continual Change of the
Area of Distribution by Elevations and Depressions of the Ground. —
Chorological Importance of Geological Processes. — Influence of the
Change of Climate. — Ice or Glacial Period. — Its Importance to
Chorology. — Importance of Migrations for the Origin of New Species.
— Isolation of Colonists. — Wagner's Law of Migration. — Connection
between the Theory of Migration and the Theory of Selection. — Agree-
ment of its Results with the Theory of Descent.

As I have repeatedly said, but cannot too much emphasize,
the actual value and invincible strength of the Theory
of Descent does not lie in its explaining this or that single
phenomenon, but in the fact that it explains all biological
phenomena, that it makes all botanical and zoological
series of phenomena intelligible in their relations to one
another. Hence every thoughtful investigator is the more
firmly and deeply convinced of its truth the more he
advances from single biological observations to a general
view of the whole domain of animal and vegetable life*

364 THE HISTORY OF CREATION.

Let us now, starting from this comprehensive point of view,
survey a biological domain, the varied and complicated
phenomena of which may be explained with remarkable
simplicity and clearness by the theory of descent. I mean
Chorology, or the theory of the local distribution of
organisms over the surface of the earth. By this 1 do
not only mean the geographical distribution of animal
and vegetable species over the different parts and provinces
of the earth, over continents and islands, seas, and rivers ;
but also their topographical distribution in a vertical
direction, their ascending to the heights of mountains, and
their descending into the depths of the ocean.

The strange chorological series of phenomena which
show the horizontal distribution of organisms over parts
of the earth, and their vertical distribution in heights and
depths, have long since excited general interest. In recent
times Alexander Humboldt 39 and Frederick Schouw have
especially discussed the geography of plants, and Berghaus,
Schmarda, and Wallace the geography of animals, on a
large scale. But although these and several other naturalists
have in many ways increased our knowledge of the dis-
tribution of animal and vegetable forms, and laid open to
us a new domain of science, full of wonderful and interest-
ing phenomena, yet Chorology as a whole remained, as
far as their labours were concerned, only a desultory know-
ledge of a mass of individual facts. It could not be called
a science as long as the causes for the explanation of these
facts were wanting. These causes were first disclosed by
the theory of selection and its doctrine of the migrations
of animal and vegetable species, and it is only since Darwin
that we have been able to speak of an independent science

MIGRATIONS OF ORGANISMS. 365

of Chorology. Wallace and Moritz Wagner have done most,
after Darwin, in this respect.

The first naturalist who clearly comprehended the theory
of migration and correctly recognized its importance for the
origin of new species, was the celebrated German geologist,
Leopold Buch. In his " Physical Description of the Canary
Island," as early as 1825 — hence thirty-four years before the
appearance of Darwin's work — he made those remarkable
propositions which I have already quoted in my fifth
chapter. He there states that the migration, distribution,
and local separation of species are the three principal
outward causes that effect the transformation of species ;
their influence, he thinks, is sufficient to produce new
species by the internal interaction of variability and
heredity. Buch, who was a great traveller and had made
extensive observations himself, also discusses the great
importance exercised by the local separation of animals and
plants that have migrated to isolated islands. Unfortunately,
this eminent geologist did not work this important idea
out further, and was unable to convince his friend, Alexander
Humboldt, of its great significance. Wagner, however, in
his essay on Leopold Buch and Darwin (1883), has very
justly pointed out that, with regard to the migration-theory,
Buch must be looked upon as Darwin's greatest predecessor.

If all the phenomena of the geographical and topo-
graphical distribution of organisms are examined by them-
selves, without considering the gradual development of
species, and if at the same time, following the customary
superstition, the individual species of animals and plants
are considered as forms independently created and in-
dependent of one another, then there remains nothing for

366 THE HISTOEY OF CREATION.

us to do but to gaze at those phenomena as a confused
collection of incomprehensible and inexplicable miracles.
But as soon as we leave this low standpoint, and rise to
the height of the theory of development, by means of the
supposition of a blood-relationship between the different
species, then all at once a clear light falls upon this strange
series of miracles, and we see that all chorological facts can
be understood quite simply and clearly by the supposition
of a common descent of the species, and their passive and
active migrations.

The most important principle from which we must start
in chorology, and of the truth of which we are convinced
by due examination of the theory of selection, is that, as a
rule, every animal and vegetable species has arisen only
once in the course of time and only in one place on the
earth — its so-called " centre of creation " — by natural
selection. I share this opinion of Darwin's unconditionally,
in respect to the great majority of higher and perfect
organisms, and in respect to most animals and plants in
which the division of labour, or differentiation of the cells
and organs of which they are composed, has attained a
certain stage. For it is quite incredible, or could at best
only be an exceedingly rare accident, that all the manifold
and complicated circumstances — all the different conditions
of the struggle for life, which influence the origin of a new
species by natural selection — should have worked together
in exactly the same agreement and combination more than
once in the earth's history, or should have been active at
the same time at several different points of the earth's
surface.

On the other hand, I consider it very probable that

CENTRES OP CREATION. 367

certain exceedingly imperfect organisms of the simplest
structure, forms of species of an exceedingly indifferent
nature, as, for example, many single-celled Protista (Algse
as well as Amoebae and Infusoria), but especially the Monera,
the simplest of them all, have several times or simultaneously
arisen in their specific form in several parts of the earth.
For the few and very simple conditions by which their
specific form was changed in the struggle for life may
surely have often been repeated, in the course of time,
independently in different parts of the earth. Further,
those higher specific forms also, which have not arisen by
natural selection, but by hybridism (the previously men-
tioned hybrid species, pp. 150 and 151), may have repeatedly
arisen anew in different localities. As, however, this pro-
portionately small number of organisms does not especially
interest us here, we may, in respect of chorology, leave
them alone, and need only take into consideration the
distribution of the great majority of animal and vegetable
species in regard to which the single origin of every species
in a single locality, in its so-called " central point of
creation," can be considered as tolerably certain.

Every animal and vegetable species from the beginning
of its existence has possessed the tendency to spread beyond
the limited locality of its origin, beyond the boundary of
its "centre of creation," or, in other words, beyond its
primaeval home, or its natal place. This is a necessary
consequence of the relations of population and over-popula-
tion. The more an animal or vegetable species increases,
the less is its limited natal place sufficient for its sustenance,
and the fiercer the struggle for life ; the more rapid the
over-population of the natal spot, the more it leads to

368 THE HISTORY OF CREATION.

emigration. These migrations are common to all organ-
isms, and are the real cause of the wide distribution
of the different species of organisms over the earth's
surface. Just as men leave over-crowded states, so all
animals and plants migrate from their over-crowded
primeval homes.

Many distinguished naturalists, especially Leopold Buch,
Lyell, 11 and Schleiden, have before this repeatedly drawn
attention to the great importance of these very interesting
migrations of organisms. The means of transport by which
they are effected are extremely varied. Darwin has dis-
cussed these most excellently in the eleventh and twelfth
chapters of his work, which are exclusively devoted to
" geographical distribution." The means of transport are
partly active, partly passive ; that is to say, the organism
effects its migration partly by free locomotion due to its
own activity, and partly by the movements of other natural
bodies in which it has no active share.

It is self-evident that active migrations play the chief
part in animals able to move freely. The more freely an
animal's organization permits it to move in all directions,
the more easily the animal species can migrate, and the
more rapidly it will spread over the earth. Flying animals
are of course most favoured in this respect, among vertebrate
animals especially birds, and among articulated animals,
insects. These two classes, as soon as they came into
existence, can have more easily spread over the whole earth
than any other animal, and this fact partly explains the
extraordinary uniformity of structure which characterizes
these two great classes of animals. For, although they
contain an exceedingly large number of different species,

MEANS OF TRANSPORT. 369

and although the insect class alone is said to possess more
different species than all other classes of animals together,
yet all the innumerable species of insects, and in like
manner, also, the different species of birds, agree most
strikingly in all essential peculiarities of their organization.
Hence, in the class of insects, as well as in that of birds,
we can distinguish only a very small number of large
natural groups or orders, and these few orders differ but
very little from one another in their internal structure.
The orders of birds with their numerous species are not
nearly as distinct from one another as the orders of the
mammalian class, containing much fewer species ; and the
orders of insects, which are extremely rich in genera and
species, resemble one another much more closely in their
internal structure than do the much smaller orders of the
crab class. The general parallelism between birds and
insects is also very interesting in relation to systematic
zoology; and the great importance of their richness in
forms, for scientific morphology, lies in the fact that they
show us how, within the narrowest anatomical sphere, and
without profound changes of the essential internal organiza-
tion, the greatest variety in external bodily forms can be
attained. The reason of this is evidently their flying mode
of life and their free locomotion. In consequence of this,
birds, as well as insects, have spread very rapidly over the
whole surface of the earth, have settled in all possible
localities inaccessible to other animals, and variously
modified their specific form by superficial adaptation to
particular local relations.

Of the flying vertebrates, bats are, moreover, of peculiar
interest to chorology. For not a single island lying more

vol. 1. 2 b

370 THE HISTOEY OF CEEATION.

than 300 miles from the nearest continent possesses other
indigenous mammals from the mainland. On the other
hand, numerous species of hat may be found on isolated
islands, and many separate islands or groups of islands are
distinguished for possessing quite peculiar species or even of
peculiar species of bats. This remarkable fact is most
easily accounted for by the theory of selection and migra-
tion, whereas it remains an unintelligible mystery without
it. Land mammals, which cannot fly, are not able to
wander across broad stretches of sea and to search far-off
islands. This is possible only to bats, which can fly for
some length of time, and are, moreover, easily carried
hundreds of miles by storms. And when cast upon distant
islands they have to adapt themselves to wholly different
conditions of existence, and their descendants sooner or
later become transformed into new species or even into new
generic forms.

Next to the flying animals, those animals, of course, have
spread most quickly and furthest which were next best
able to migrate, that is, the best runners among the
inhabitants of the land, and the best swimmers among the
inhabitants of the water. However, the power of such
active migrations is not confined to those animals which
throughout life enjoy free locomotion. For the fixed
animals also, such as corals, tubicolous worms, sea-squirts,
lily encrinites, sea-acorns, barnacles, and many other lower
animals which adhere to seaweeds, stones, etc., enjoy, at
least at an early period of life, free locomotion. They all
migrate before they adhere to anything. Their first [free
locomotive condition of early life is generally that of a
"ciliated" larva, a roundish, cellular corpuscle, which, by

PASSIVE MIGRATION. 37 1

means of a garb of movable " flimmer-hairs " (Latin, " cilia "),
swarms about in tbe water. All of tbese swimming ciliated
larvae of the lower animals have developed out of the same
common germinal form, that is, out of the (?as£raJa (Plate V.,
Fig. 8, 18); and it too is originally capable of migrating,
owing to its garb of movable " flimmer-hairs."

But the power of free locomotion, and hence, also, of active
migration, is not confined to animals alone, but many plants
likewise enjoy it. Many lower aquatic plants, especially the
class of the Tangles (Algae), swim about freely in the water
in early life, like the lower animals just mentioned, by
means of a vibratile hairy coat, a vibrating whip, or a
covering of tremulous fringes, and only at a later period
adhere to objects. Even in the case of many higher plants,
which we designate as creepers and climbing plants, we
may speak of active migration. Their elongated stalks and
perennial roots creep or climb during their long process of
growth to new positions, and by means of their widespread
branches they acquire new habitations, to which they
attach themselves by buds, and bring forth new colonies
of individuals of their species.

Influential as these active migrations of most animals
and many plants are, yet alone they would by no means
be sufEcient to explain the chorology of organisms. Passive
migrations have ever been by far the more important, and
of far greater influence, in the case of most plants and in
that of many animals. Such passive changes of locality
are produced by extremely numerous causes. Air and
water in their eternal motion, wind and waves with their
manifold currents, play the chief part. The : wind in all
places and at all times raises light organisms, small animals

372 THE HISTOEY OF CREATION.

and plants, but especially their young germs, animal eggs
and plant seeds, and carries them far over land and seas.
Where they fall into the water they are seized by currents
or waves and carried to other places. It is well known,
from numerous examples, how far in many cases trunks of
trees, hard-shelled fruits, and other not readily perishable
portions of plants are carried away from their original home
by the course of rivers and by the currents of the sea.
Trunks of palm trees from the West Indies are brought by
the Gulf Stream to the British and Norwegian coasts. All
large rivers bring down driftwood from the mountains, and
frequently Alpine plants are carried from their home at the
source of the river into the plains, and even further, down
to the sea. Frequently numerous creatures live between
the roots of the plants thus carried down, and between the
branches of the trees thus washed away there are various
inhabitants which have to take part in the passive migra-
tion. The bark of the tree is covered with mosses, lichens,
and parasitic insects. Other insects, spiders, etc., even
small reptiles aud mammals, are hidden within the hollow
trunk or cling to the branches. In the earth adhering to
the fibres of the roots, in the dust lying in the cracks of
the bark, there are innumerable germs of smaller animals
and plants. Now, if the trunk thus washed away lands
safely on a foreign shore or on a distant island, the guests
who had to take part in the involuntary voyage can leave
their boat and settle in the new country. A very remark-
able kind of water-transport is formed by the floating ice-
bergs which annually become loosened from the eternal ice
of the Polar Sea. Although these cold regions are thinly
peopled, yet many of their inhabitants, who were accidentally

MODES OF MIGKATION. ,373

upon an iceberg while it was becoming loosened, are carried
away with it by the currents, and landed on warmer shores.
In this manner, by means o£ loosened blocks of ice from
the northern Polar Sea, often whole populations of small
animals and plants have been carried to the northern shores
of Europe and America. Nay, even polar foxes and polar
bears have been carried in this way to Iceland and to the
British Isles.

Transport by air is no less important than transport by
water in this matter of passive migration. The dust cover-
ing our streets and roofs, the earth lying on dry fields and
dried-up pools, the light moist soil of forests, in short, the
whole surface of the globe, contains millions of small organ-
isms and their germs. Many of these small animals and
plants can without injury become completely dried up, and
awake again to life as soon as they are moistened. Every
gust of wind raises up with the dust innumerable little
creatures of this kind, and often carries them away to other
places miles off. But even larger organisms, and especially
their germs, may often make distant passive journeys
through the air. The seeds of many plants are provided
with light feathery processes, which act as parachutes and
facilitate their flight in the air, and prevent their falling.
Spiders make journeys of many miles through the air on
their fine filaments, their so-called gossamer threads. Young
frogs are frequently raised by whirlwinds into the air by
thousands, and fall down in a distant part as a " shower of
frogs." Storms may carry birds and insects across half the
earth's circumference. They drop in the United States,
having risen in England. Starting from California, they
only come to rest in China. But, again, many other

374 THE HISTORY OF CREATION.

organisms may make the journey from one continent to
another together with the birds and insects. Of course all
parasites, the number of which is legion, fleas, lice, mites,
moulds, etc., migrate with the organism upon which they
live. In the earth which often remains sticking to the
claws of birds there are also small animals and plants or
their germs. Thus the voluntary or involuntary migration
of a single larger organism may carry a whole small flora
and fauna from one part of the earth to another.

Besides the means of transport here mentioned, there are
many others which explain the distribution of animal and
vegetable species over the large tracts of the earth's surface,
and especially the general distribution of the so-called
cosmopolitan species. But these alone would not be nearly
sufficient to explain all chorological facts. How is it, for
example, that many inhabitants of fresh water live in
various rivers or lakes far away and quite apart from one
another ? How is it that many inhabitants of mountains,
which cannot exist in plains, are found upon entirely
separated and far-distant chains of mountains ? It is
difficult to believe, and in many cases quite inconceivable,
that these inhabitants of fresh water should have in any
way, actively or passively, migrated over the land lying
between the lakes, or that the inhabitants of mountains in
any way, actively or passively, crossed the plains lying
between their mountain-homes. But here geology comes to
our help, as a mighty ally, and completely solves these
difficult problems for us.

The history of the earth's development shows us that the
distribution of land and water on its surface is ever and
continually changing. In consequence of geological changes

CHANGES OF LAND AND WATER. 375

of the earth's crust, elevations and depressions of the ground
take place everywhere, sometimes more strongly marked in
one place, sometimes in another. Even if they happen so
slowly that in the course of centuries the seashore rises or
sinks only a few inches, or even only a few lines, still they
nevertheless effect great results in the course of long periods
of time. And long — immeasurably long — periods of time
have not been wanting in the earth's history. During the
course of many millions of years, ever since organic life ex-
isted on the earth, land and water have perpetually struggled
for supremacy. Continents and islands have sunk into the
sea, and new ones have arisen out of its bosom. Lakes and
seas have slowly been raised and dried up, and new water-
basins have arisen by the sinking of the ground. Peninsulas
have become islands by the narrow neck of land which
connected them with the mainland sinking into the water.
The islands of an archipelago have become the peaks of a
continuous chain of mountains by the whole floor of their
sea being considerably raised.

Thus the Mediterranean at one time was an inland sea,
when, in the place of the Straits of Gibraltar, an isthmus
connected Africa with Spain. England, even during the
more recent history of the earth, when man already existed,
has repeatedly been connected with the European continent
and been repeatedly separated from it. Nay, even Europe
and North America have been directly connected. The
South Sea at one time formed a large Pacific continent, and
the numerous little islands which now lie scattered in it
were simply the highest peaks of the mountains covering
that continent. The Indian Ocean formed a continent
which extended from the Sunda Islands along the southern

376 THE HISTORY OE CREATION.

coast of Asia to the east coast of Africa. This large con-
tinent of former times Sclater, an Englishman, has called
Lemwria, from the monkey-like animals which inhabited it,
and it is at the same time of great importance from being
the probable cradle of the human race, which in all likeli-
hood here first developed out of anthropoid apes. The
important proof which Alfred Wallace has furnished, 36 by
the help of chorological facts, that the present Malayan
Archipelago consists in reality of two completely different
divisions, is particularly interesting. The western division,
the Indo-Malayan Archipelago, comprising the large islands
of Borneo, Java, and Sumatra, was formerly connected by
Malacca with the Asiatic continent, and probably also with
the Lemurian continent just mentioned. The eastern
division, on the other hand, the Austro-Malayan Archipelago,
comprising Celebes, the Moluccas, New Guinea, Solomon's
Islands, etc., was formerly directly connected with Australia.
Both divisions were formerly two continents separated by
a strait, but they have now for the most part sunk below
the level of the sea. Wallace, solely on the ground of his
accurate chorological observations, has been able in the
most acute manner to determine the position of this former
strait, the south end of which passes between Bali and
Lombok. And this deep strait, although only fifteen miles
broad, still forms a sharp boundary between the islands of
Bali and Lombok ; the fauna of Bali belongs to further
India, the fauna of the latter to Australia.

Thus, ever since liquid water existed on the earth, the
boundaries of water and land have eternally changed, and
we may assert that the outlines of continents and islands
have never remained for an hour, nay, even for a minute,

GEOLOGICAL CHANGES. 377

exactly the same. For the waves eternally and perpetually
break on the edge of the coast, and whatever the land in
these places loses in extent, it gains in other places by the
accumulation of mud, which condenses into solid stone and
again rises above the level of the sea as new land. Nothing
can be more erroneous than the idea of a firm and un-
changeable outline of our continents, such as is impressed
upon us in early youth by defective lessons in geography,
which are devoid of a geological basis.

I need hardly draw attention to the fact that these
geological changes of the earth's surface have ever been
exceedingly important to the migrations of organisms, and
consequently to their Chorology. From them we learn to
understand how it is that the same or nearly related species
of animals and plants can occur on different islands,
although they could not have passed through the water
separating them, and how other species living in fresh
water can inhabit different enclosed water-basins, although
they could not have crossed the land lying between them.
These islands were formerly mountain-peaks of a connected
continent, and these lakes were once directly connected
with one another. The former were separated by geological
depressions, the latter by elevations. Now, if we further
consider how often and how unequally these alternating
elevations and depressions occur on the different parts of
the earth, and how, in consequence of this, the boundaries
of the geographical tracts of distribution of species become
changed, and if we further consider in what exceedingly
various ways the active and passive migrations of organisms
must have been influenced by them, then we shall be in a
position to completely understand the great variety of the

378 THE HISTORY OF CREATION.

picture which is at present offered to us by the distribution
of animal and vegetable species.

There is yet another important circumstance to be men-
tioned here, which is likewise of great importance for a
complete explanation of this varied geographical picture,
and which throws light upon many very obscure facts,
which, without its help, we should not be able to compre-
hend. I refer to the gradual change of climate which has
taken place during the long course of the organic history
of the earth. As we saw in our last chapter, at the be-
ginning of organic life on the earth a much higher and
more equal temperature must have generally prevailed than
at present. The differences of zones, which in our time are
so very striking, did not exist at all in those times. It is
probable that for many millions of years but one climate
prevailed over the whole earth, which very closely re-
sembled, or even surpassed, the hottest tropical climate of the
present day. The highest north which man has yet reached
was then covered with palms and other tropical plants, the
fossil remains of which are still found there. The tempera-
ture of this climate at a later period gradually decreased ;
but still the poles remained so warm that the whole surface
of the earth could be inhabited by organisms. It was only
at a comparatively very recent period of the earth's history,
namely, at the beginning of the tertiary period, that there
occurred, as it seems, the first perceptible cooling of the
earth's crust at the poles, and through this the first differen-
tiation or separation of the different zones of temperature
or climatic zones. But the slow and gradual decrease of
temperature continued to extend more and more within the
tertiary period, until at last, at both poles of the earth, the
first permanent ice-caps were formed.

THE QUATERNABY PERIOD. 379

I need scarcely point out in detail how very much this
change of climate must have affected the geographical dis-
tribution of organisms, and the origin of numerous new
species. The animal and vegetable species, which, down
to the tertiary period, had found an agreeable tropical
climate all over the earth, even as far as the poles, were
now forced either to adapt themselves to the intruding cold,
or to flee from it. Those species which adapted and accus-
tomed themselves to the decreasing temperature became
new species simply by this very acclimatization, under the
influence of natural selection. The other species, which
fled from the cold, had to emigrate and seek a milder
climate in lower latitudes. The tracts of distribution
which had hitherto existed must by this have been vastly
changed.

However, during the last great period of the earth's
history, during the quaternary period (or diluvial period)
succeeding the tertiary one, the decrease of the heat of the
earth from the poles did not by any means remain
stationary. The temperature fell lower and lower, nay,
even far below the present degree. Northern and Central
Asia, Europe, and North America from the north pole, were
covered to a great extent by a connected sheet of ice, which
in our part of the earth seems to have reached the Alps.
In a similar manner the cold also advancing from the south
pole covered a large portion of the southern hemisphere,
which is now free from it, with a rigid sheet of ice. Thus,
between these vast lifeless ice continents there remained
only a narrow zone to which the life of the organic world
had to withdraw. This period, during which man, or at
least the human ape, already existed, and which forms the

380 THE HISTORY OP CREATION.

first period of the so-called diluvial epoch, is now universally
known as the ice or glacial period.

The ingenious Carl Schimper is the first naturalist who
clearly conceived the idea of the ice period, and proved the
great extent of the former glaciation of Central Europe by
the help of the so-called boulders, or erratic blocks of stone,
as also by the " glacier tables." Louis Agassiz, stimulated
by him, and considerably supported by the independent
investigations of the eminent geologist Charpentier, after-
wards undertook the task of carrying out the theory of the
ice period. In England, the geologist Forbes distinguished
himself in this matter, and was also the first to apply it to
the theory of migrations and the geographical distribution
of species dependent upon migration. Agassiz, however,
afterwards injured the theory by his one-sided exaggeration,
inasmuch as, from his partiality to Cuvier's theory of
cataclysms, he endeavoured to attribute the destruction of
the whole animate creation then existing, to the sudden
coming on of the cold of the ice period and the " revolu-
tion " connected with it.

It is unnecessary here to enter into detail as to the ice
period itself, and into investigations about its limits, and
I may omit this all the more reasonably since the whole of
our recent geological literature is full of it. It will be
found discussed in detail in the works of Cotta, 81 Lyell, 80
Zittel, 82 etc. Its great importance to us here is that it
helps us to explain the most difficult chorological problems,
as Darwin has correctly perceived.

For there can be no doubt that this glaciation of the
present temperate zones must have exercised an exceedingly
important influence on the geographical and topographical

GLACIAL PERIODS. 38 1

distribution of organisms, and that it must have entirely
changed it. While the cold slowly advanced from the poles
towards the equator, and covered land and sea with a
connected sheet of ice, it must of course have driven the
whole living world before it. Animals and plants had to
migrate if they wished to escape being frozen. But as at
that time the temperate and tropical zones were probably
no less densely peopled with animals and plants than at
present, there must have arisen a fearful struggle for life
between the latter and the intruders coming from the poles.
During this struggle, which certainly lasted many thousands
of years, many species must have perished and many become
modified and been transformed into new species. The
hitherto existing tracts of distribution of species must have
become completely changed, and the struggle have been
continued, nay, indeed, must have broken out anew and
been carried on in new forms, when the ice period had
reached and gone beyond its furthest point, and when in
the post-glacial period the temperature again increased, and
organisms began to migrate back again towards the poles.

In any case this great change of climate, whether a
greater or less importance be ascribed to it, is one of those
occurrences in the history of the earth which have most
powerfully influenced the distribution of organic forms.
But more especially one important and difficult chorological
circumstance is explained by it in the simplest manner,
namely, the specific agreement of many of our Alpine in-
habitants with some of those living in polar regions. There
are a great number of remarkable animal and vegetable
forms which are common to these two far distant parts of
the earth, and which are found nowhere in the wide plains

382 THE HISTORY OF CREATION.

lying between them. Their migration from the polar lands
to the Alpine heights, or vice versd, would be inconceivable
under the present climatic circumstances, or could be
assumed at least only in a few rare instances. But such a
migration could take place, nay, was obliged to take place,
during the gradual advance and retreat of the ice-sheet. As
the glaciation encroached from Northern Europe towards our
Alpine chains, the polar inhabitants retreating before it —
gentian, saxifrage, polar foxes, and polar hares — must have
peopled Germany, in fact all Central Europe. When the
temperature again increased, only a portion of these Arctic
inhabitants returned with the retreating ice to the Arctic
zones. Another portion of them climbed up the mountains
of the Alpine chain instead, and there found the cold climate
suited to them. The problem is thus solved in a most
simple manner.

We have hitherto principally considered the theory of the
migrations of organisms in so far as it explains the radia-
tion of every animal and vegetable species from a single
primaeval home, from a " central point of creation," and the
dispersion of these species over a greater or less portion of
the earth's surface. But these migrations are also of great
importance to the theory of development, because we can
perceive in them a very important means for the origin of
new species. When animals and plants migrate they meet
in their new home, in the same way as do human emigrants,
with conditions which are more or less different from those
which they have inherited throughout generations, and to
which they have been accustomed. The emigrants must
either submit and adapt themselves to these new conditions
of life or they perish. By adaptation their peculiar specific

INFLUENCE OF MIGRATION. 383

character becomes the more changed the greater the differ-
ence between the new and the old home. The new climate,
the new food, but, above all, new neighbours in the forms
of other animals and plants, influence and tend to modify
the inherited character of the immigrant species, and if it is
not hardy enough to resist the influences, then sooner or
later a new species must arise out of it. In most cases
this transformation of an immigrant species takes place so
quickly under the influence of the altered struggle for life,
that even after a few generations a new species arises
from it.

Migration has an especial influence in this way on
Gonochoristis, i.e. on all organisms with separate sexes.
For in them the origin of new species by natural selection
is always rendered difficult, or delayed, by the fact that the
modified descendants occasionally again mix sexually with
the unchanged original form, and thus by crossing return
to the first form. But if such varieties have migrated, if
great distances or barriers to migration — seas, mountains,
etc. — have separated them from the old home, then the
danger of a mingling with the primary form is prevented,
and the isolation of the emigrant form, which becomes a
new species by adaptation, prevents its breeding with the
old stock, and hence prevents its return in this way to the
original form.

The importance of migration for the isolation of newly
originating species and the prevention of a speedy return
to the primary form has been especially pointed out by the
philosophic traveller, Moritz Wagner, of Munich. In a
special treatise on " Darwin's Theory and the Law of the
Migration of Organisms," Wagner gives from his own

384 THE HISTOEY OF CREATION.

rich experience a great number of striking examples which
confirm the theory of migration set forth by Darwin in
the eleventh and twelfth chapters of his book, where he
especially discusses the effect of the complete isolation of
emigrant organisms in the origin of new species. Wagner
sets forth the simple causes which have " locally bounded
the form and founded its typical difference," in the follow-
ing three propositions : — 1. The greater the total amount
of change in the hitherto existing conditions of life which
the emigrating individuals find on entering a new territory,
the more intensely must the innate variability of every
organism manifest itself. 2. The less this increased indi-
vidual variability of organisms is disturbed in the peaceful
process of reproduction by the mingling of numerous subse-
quent immigrants of the same species, the more frequently
will nature succeed, by intensification and transmission of
the new characteristics, in forming a new variety or race,
that is, a commencing species. 3. The more advantageous
the changes experienced by the individual organs are to the
variety, the more readily will it be able to adapt itself to
the surrounding conditions; and the longer the undisturbed
breeding of a commencing variety of colonists in a new
territory continues without its mingling with subsequent
immigrants of the same species, the oftener a new species
will arise out of the variety.

Every one will agree with these three propositions of
Moritz Wagner's. But we must consider his view, that the
migration and the subsequent isolation of the emigrant
individuals is a necessary condition for the origin of new
species, to be completely erroneous. Wagner says, " with-
out a long-enduring separation of colonists from their former

WAGNER'S THEORIES. 385

species, the formation of a new race cannot succeed — selec-
tion, in fact, cannot take place. Unlimited crossing, un-
hindered sexual mingling of all individuals of a species, will
always produce uniformity, and drive varieties, whose
characteristics have not been fixed throughout a series of
generations, back to the primary form."

This sentence, in which Wagner himself comprises the
main result of his investigations, he would be able to defend
only if all organisms were of separate sexes, if every origin
of new individuals were possible only by the mingling of
male and female individuals. But this is by no means
the case. Curiously enough, Wagner says nothing of the
numerous hermaphrodites which, possessing both the sexual
organs, are capable of self-fructification, and likewise
nothing of the countless organisms which are not sexually
differentiated.

Now, from the earliest times of the organic history of the
earth, there have existed thousands of organic species
(thousands of which still exist) in which no difference of
sex whatever exists, and, in fact, in which no sexual propa-
gation takes place, and which exclusively reproduce them-
selves in a non-sexual manner by division, budding, forma-
tion of spores, etc. All the great mass of Protista, the
Monera, Amoebae, Myxomycetes, Rhizopoda, Infusoria, etc.,
in short, all the lower organisms which we shall have to
enumerate in the domain of Protista, standing midway
between the animal and vegetable kingdoms, propagate
themselves exclusively in a non-sexual manner. And this
domain comprises a class of organisms which is one of the
richest in forms, nay, even in a certain respect the richest
of all in forms, as all possible geometrical fundamental

vol. 1. 2 C

386 THE HISTORY OF CEEATION.

forms are represented in it. I allude to the wonderful class
of the Rhizopoda, or Ray-streamers, to which the lime-
shelled Thalamophora and the flint-shelled Radiolaria
belong. (Compare Chapters XVII. and XVIII.)

It is self-evident, therefore, that Wagner's theory is quite
inapplicable to all these non-sexual organisms. Moreover,
the same applies to all those hermaphrodites in which every
individual possesses both male and female organs and is
capable of self-fructification. This is the case, for instance,
in the Flat-worms, flukes, and tapeworms, further in the
barnacle crabs (Cirripedia), in the important Sack-worms
(Tunicates), the invertebrate relatives of the vertebrate
animals, and in very many other organisms of different
groups. Many of these species have arisen by natural
selection, without a " crossing " of the originating species
with its primary form having been possible.

As I have already shown in the eighth chapter, the origin
of the two sexes, and consequently sexual propagation in
general, must be considered as a process which began only
in later periods of the organic history of the earth, being
the result of differentiation or division of labour. The
most ancient terrestrial organisms can have propagated
themselves only in the simplest non-sexual manner. Even
now all Protista, as well as all the countless forms of cells,
which constitute the body of higher organisms, multiply
themselves only by non-sexual generation. And yet there
arise here " new species " by differentiation in consequence
of natural selection.

But even if we were to take into consideration the animal
and vegetable species with separate sexes, in this case too
we should have to oppose Wagner's chief proposition, that

INFLUENCE OP MIGRATION. 387

" the migration of organisms and their formation of colonies
is the necessary condition of natural selection." August
Weismann, in his treatise on the " Influence of Isolation
upon the Formation of Species," u has already sufficiently
refuted that proposition, and has shown that even in one
and the same district one bi-sexual species may divide itself
into several species by natural selection. In relation to
this question, I must again call to mind the great influence
exercised by division of labour and the morphological
separation of forms connected with it, and, indeed, for
the transformation of the whole organism as well as for
the cells of which it is composed. Both the personal diver-
gence as well as the cellular divergence are the necessary
consequences of natural selection. All the different kinds
of cells constituting the body of the higher organisms, the
nerve-cells, muscle-cells, gland-cells, etc., all these "good
species of Plastids," these "bonse species" of elementary
organisms, have arisen solely *by division of labour, in
consequence of natural selection, although they not only
never were locally isolated, but ever since their origin
have always existed in the closest local relations one with
another. Now, the same reasoning that applies to these
elementary organisms, or "individuals of the first order,"
applies also to the many-celled organisms of a higher order
which only at a later date have arisen as "good species"
from among their fellows.

Hence the opinions of Leopold Buch, of Darwin and of
Wallace, that the migration of organisms and their isolation
in their new home is a very advantageous condition for the
origin of new species, remain correct ; and we cannot admit,
as Wagner asserts, that it is a necessary condition, and that

388 THE HISTOEY OF CEEATION.

without it no species can arise. Wagner sets up this
opinion, "that migration is a necessary condition for natural
selection," as a special "law of migration ; " but we consider
it sufficiently refuted by the above-mentioned facts. We
have, moreover, already pointed out that in reality the
origin of new species by natural selection is a mathematical
and logical necessity which, without anything else, follows
from the simple combination of three great facts. These
three fundamental facts are — the Struggle for Life, the
Adaptability, and the Hereditivity of organisms.

We cannot here enter into detail concerning the numerous
interesting phenomena furnished by the geographical and
topographical distribution of organic species, which are all
wonderfully explained by the theory of selection and
migration. For these I refer the reader to the writings of
Darwin, 1 Wallace, 86 and Moritz Wagner, in which the im-
portant doctrine of the limits of distribution — seas, rivers,
and mountains — is excellently discussed and illustrated by
numerous examples. Only three other phenomena must be
mentioned here on account of their special importance.
First, the close relation of forms, that is, the striking "family
likeness " existing between the characteristic local forms of
every part of the globe, and their extinct fossil ancestors in
the same part of the globe ; secondly, the no less striking
" family likeness " between the inhabitants of island groups
and those of the neighbouring continent from which the
islands were peopled; lastly and thirdly, the peculiar
character presented in general by the flora and fauna of
islands taken as a whole. It was these three classes of
phenomena which first roused young Darwin (in 1832) to
the thought of the Theory of Descent.

SUFFICIENCY OF THE THEORY. 389

All these chorological facts given by Darwin, Wallace,
and Wagner — especially the remarkable phenomena of the
limited local fauna and flora, the relations of insular to
continental inhabitants, the wide distribution of the so-
called " cosmopolitan species," the close relationship of the
local species of the present day with the extinct species of
the same limited territory, the demonstrable radiation of
every species from a single central point of creation — all
these, and all other phenomena furnished to us by the geo-
graphical and the topographical distribution of organisms,
are explained in a simple and thorough manner by the
theory of selection and migration, while without it they
are simply incomprehensible. Consequently, in the whole
of this series of phenomena we find a new and weighty
proof of the truth of the Theory of Descent.

390 THE HISTORY OF CREATION.

CHAPTER XV.

THEORY OP THE DEVELOPMENT OP THE UNIVERSE
AND OP THE EARTH. SPONTANEOUS GENERA-
TION. THE CARBON THEORY. THE PLASTID
THEORY.

History of the Development of the Earth. — Kant's Theory of the Develop-
ment of the Universe, or the Cosmological Gas Theory. — Development
of Suns, Planets, and Moons. — First Origin of Water. — Comparison
of Organisms and Anorgana. — Organic and Inorganic Substances. —
Degrees of Density, or Conditions of Aggregation. — Albuminous Combi.
nations of Carbon. — Plasson-bodies. — Organic and Inorganic Forms. —
Crystals and Monera. — Formless Organisms without Organs. — Stereo-
metrical Fundamental Forms of Crystals and of Organisms. — Organic
and Inorganic Forces. — Vital Force. — Growth and Adaptationin Crystals
and in Organisms. — Formative Tendencies of Crystals. — Unity of
Organic and Inorganic Nature. — Spontaneous Generation, or Archi-
gony. — Autogony and Plasmogony. — Origin of Monera by Spontaneous
Generation. — Origin of Cells from Monera. — The Cell Theory. — The
Plastid Theory. — Plastids or Structural-Units. — Cytods and Cells. —
Four Different Kinds of Plastids.

In our considerations hitherto we have endeavoured to
answer the question, By what causes have new species of
animals and plants arisen out of existing species? We
have answered this question in so far that on the one hand
hybridism, and on the other the natural selection in the
struggle for existence — that is, the interaction of the laws
of Inheritance and Adaptation — are completely sufficient

ADHESION OF A DIVINE. 39 1

for producing mechanically the endless variety of the
different animals and plants, which have the appearance of
being organized according to a plan for a definite purpose.
Meanwhile the question must have already repeatedly pre-
sented itself to the reader, How did the first organisms, or
that one original and primaeval organism arise, from which
we derive all the others ?

This question Lamarck 2 answered by the hypothesis of
spontaneous generation, or archigony. But Darwin passes
over and avoids this subject, as he expressly remarks that
he has " nothing to do with the origin of the soul, nor with
that of life itself." At the conclusion of his work he ex-
presses himself more distinctly in the following words : " I
imagine that probably all organic beings which ever lived
on this earth descended from some primitive form, which
was first called into life by the Creator." Moreover, Darwin,
for the consolation of those who see in the Theory of
Descent the destruction of the whole "moral order of the
universe," appeals to the celebrated author and divine who
wrote to him, that " he has gradually learnt to see that it is
just as noble a conception of the Deity to believe that he
created a few original forms capable of self-development
into other and needful forms, as to believe that he required
a fresh act of creation to supply the voids caused by the
action of his laws." Those to whom the belief in a super-
natural creation is an emotional necessity may rest satisfied
with this conception. They may reconcile that belief with
the Theory of Descent ; for in the creation of a single
original organism possessing the capability to develop all
others out of itself by inheritance and adaptation, they can
really find much more cause for admiring the power and

392 THE H1ST0BY OF CREATION.

wisdom of the Creator than in the independent creation of
different species.

If, taking this point of view, we were to explain the
origin of the first terrestrial organisms, from which all the
others are descended, as due to the action of a personal
Creator acting according to a definite plan, we should of
course have to renounce all scientific knowledge of the
process, and pass from the domain of true science to the
completely distinct domain of poetical faith. By assuming
a supernatural act of creation we should be taking a leap
into the inconceivable. Before we decide upon this latter
step, and thereby renounce all pretension to a scientific
knowledge of the process, we are at all events in duty
bound to endeavour to examine it in the light of a
mechanical hypothesis. We must at least examine whether
this process is really so wonderful, and whether we cannot
form a tenable conception of a completely non-miraculous
origin of the first primary organism. We might then be
able entirely to reject miracle in creation.

It will be necessary for this purpose, first of all, to go
back further into the past, and to examine the history of
the creation of the earth. Going back still further, we
shall find it necessary to consider the history of the creation
of the whole universe in its most general outlines. All my
readers undoubtedly know that from the structure of the
earth, as it is at present known to us, the notion has been
derived, and as yet has not been refuted, that its interior
is in a fiery fluid condition, and that the firm crust, com-
posed of different strata, on the surface of which organisms
are living, forms only a very thin pellicle or shell round
the fiery fluid centre. We have arrived at this idea by

DEVELOPMENT OP THE EARTH. 393

different confirmatory experiments and reasonings. In the
first place, the observation that the temperature of the
earth's crust continually increases towards the centre is in
favour of this supposition. The deeper we descend, the
greater the warmth of the ground, and in such proportion,
that with every 100 feet the temperature increases about
one degree. At a depth of six miles, therefore, a heat of
1500° would be attained, sufficient to keep most of the firm
substances of our earth's crust in a molten, fiery fluid state.
This depth, however, is only the 286th part of the whole
diameter of the earth (1717 miles). We further know that
springs which rise out of a considerable depth possess a
very high temperature, and sometimes even throw water
up to the surface in a boiling state. Lastly, very important
proofs are furnished by volcanic phenomena, the eruption
of fiery fluid masses of stone bursting through certain parts
of the earth's crust. The glowing heat of the streams of
lava, upon issuing from the interior of the earth, shows a
temperature of 2000° and more. All these phenomena lead
us with great certainty to the important assumption that
the firm crust of the earth forms only quite a small fraction,
not nearly the one-thousandth part of the whole diameter
of the terrestrial globe, and that the rest is still for the most
part in a molten or fiery fluid state.

Now if, starting with this assumption, we reflect on the
ancient history of the development of the globe, we are
logically carried back a step further, namely, to the assump-
tion that at an earlier date the whole earth was a fiery
fluid body, and that the formation of a thin, stiffened crust
on the surface was only a later process. Only gradually,
by radiating its intrinsic heat into the cold space of the

394 THE HISTORY OF CREATION.

universe, has the surface of the glowing ball become con-
densed into a thin crust. That the temperature of the earth
in remote times was much higher than it is now, is proved
by many phenomena. Among other things, this is rendered
probable by the equal distribution of organisms in remote
times of the earth's history. While at present, as is well
known, the different populations of animals and plants
correspond to the different zones of the earth and their
appropriate temperature, in earlier times this was distinctly
not the case. And we see from the distribution of fossils
in the remoter ages, that it was only at a very late date, in
fact, at a comparatively recent period of the organic history
of the earth (at the beginning of the so-called csenolithic
or tertiary period), that a separation of zones and of the
corresponding organic populations occurred. During the
immensely long primary and secondary periods, tropical
plants, which require a very high degree of temperature,
lived not only in the present torrid zone, under the equator,
but also in the present temperate and frigid zones. Many
other phenomena also demonstrate a gradual decrease of
the temperature of the globe as a whole, and especially a
late and gradual cooling of the earth's crust about the
poles. Bronn, in his excellent " Investigations of the Laws
of Development of the Organic World," has collected
numerous geological and palseontological proofs of this fact.
These phenomena and the mathematico-astronomical
knowledge of the structure of the universe justify the
theory that, inconceivable ages ago, long before the first
existence of organisms, the whole earth was a fiery fluid
globe. Now, this theory corresponds with the grand theory
of the origin of the universe, and especially of our planetary

GASEOUS CONDITION OF THE UNIVERSE. 395

system, which, on the ground of mathematical and astro-
nomical facts, was put forward in 1755 by our critical
philosopher Kant, 22 and was later more thoroughly estab-
lished by the celebrated mathematicians, Laplace and
Herschel. This mechanical cosmogony, or theory of the
development of the universe, is now almost universally
acknowledged ; it has not been replaced by a better one,
and mathematicians, astronomers, and geologists have con-
tinually, by various arguments, strengthened its position.

Kant's cosmogony maintains that the whole universe,
inconceivable ages ago, consisted of a gaseous chaos. All
the substances which are found at present separated on the
earth, and other bodies of the universe, in different con-
ditions of density — in the solid, semi-fluid, liquid, and elastic
fluid or gaseous states of aggregation — originally constituted
together one single homogeneous mass, equally filling up
the space of the universe, which, in consequence of an
extremely high degree of temperature, was in an exceed-
ingly thin gaseous or nebulous state. The millions of
bodies in the universe which at present form the different
solar systems did not then exist. They originated only in
consequence of a universal rotatory movement, or rotation,
during which a number of masses acquired greater density
than the remaining gaseous mass, and then acted upon the
latter as central points of attraction. Thus arose a separa-
tion of the chaotic primary nebula, or gaseous universe, into
a number of rotating nebulous spheres, which became more
and more condensed. Our solar system was such a gigantic
gaseous or nebulous ball, all the particles of which revolved
round a common central point, the solar nucleus. The
nebulous ball itself, like all the rest, in consequence of its

396 THE HISTOBY OP CEEATION.

rotatory movement, assumed a spheroidal or a flattened
globular form.

While the centripetal force attracted the rotating particles
nearer and nearer to the firm central point of the nebulous
ball, and thus condensed the latter more and more, the
centrifugal force, on the other hand, always tended to
separate the peripheral particles further and further from
it, and to hurl them off. On the equatorial sides of the
ball, which was flattened at both poles, this centrifugal
force was strongest, and as soon as, by increase of density,
it attained predominance over the centripetal force, a circular
nebulous ring separated itself from the rotating ball. This
nebulous ring marked the course of future planets. The
nebulous mass of the ring gradually condensed, and became
a planet, which revolved round its own axis, and at the
same time rotated round the central body. In precisely
the same manner, from the equator of the planetary mass,
as soon as the centrifugal force gained predominance over
the centripetal force, new nebulous rings were ejected,
which moved round the planets as the latter moved round
the sun. These nebulous rings, too, became condensed into
rotating balls. Thus arose the moons, only one of which
moves round our earth, whilst four move round Jupiter,
and six round Uranus. The ring of Saturn still shows us
a moon in its early stage of development. As by increasing
refrigeration these simple processes of condensation and
expulsion repeated themselves over and over again, there
arose the different solar systems, the planets rotating round
their central suns, and the satellites or moons moving round
their planets.

The original gaseous condition of the rotating bodies of

KANT'S GAS THEORY. 397

the universe gradually changed, by increasing refrigeration
and condensation, into the fiery fluid or molten state of
aggregation. By the process of condensation, a great
quantity of heat was emitted, and the rotating suns, planets,
and moons soon changed into glowing balls of fire, like
gigantic drops of melted metal, which emitted light and
heat. By loss of heat, the melted mass on the surface of
the fiery fluid ball became further condensed, and thus arose
a thin, firm crust, which enclosed a fiery fluid nucleus. In
all essential respects our mother earth probably did not
differ from the other bodies of the universe.

In view of the object of these pages, it will not be of
especial interest to follow in detail the history of the natural
creation of the universe, with its different solar and planetary
systems, and to establish it mathematically by the different
astronomical and geological proofs. The outlines of it,
which I have just mentioned, must be sufficient here, and
for further details I refer to Kant's * " General History of
Nature and Theory of the Heavens," 22 and to Carus Sterne's
admirable work, "The Coming into Existence and the
Passing Away " ("Werden und Vergehen"). 26 I will only add
that this wonderful theory, which might be called the cosmo-
logical gas theory, harmonizes with all the general series of
phenomena at present known to us, and stands in no irre-
concilable contradiction to any one of them. Moreover, it
is purely mechanical or monistic, makes use exclusively of
the inherent forces of eternal matter, and entirely excludes
every supernatural process, every prearranged and conscious
action of a personal Creator. Kant's Cosmological Gas
Theory consequently occupies a similar supreme position in
* " Allgemeine Naturgeschiolite und Theorie des Himmels."

398 THE HISTOKY OF CREATION. .

Anorganology, especially in Geology, and forms the crown
of our knowledge in that department, in the same way as
Lamarck's Theory of Descent does in Biology, and especially
in Anthropology. Both rest exclusively upon mechanical
or unconscious causes (causae efficientes), in no case upon
prearranged or conscious causes (causae finales). Both
therefore fulfil all the demands of a scientific theory, and
consequently will remain generally acknowledged until they
are replaced by better ones.

I will, however, not deny that Kant's grand cosmogony
has some weak points, which prevent our placing the same
unconditional confidence in it as in Lamarck's Theory of
Descent. The notion of an original gaseous chaos filling
the whole universe presents great difficulties of various
kinds. A great and unsolved difficulty lies in the fact that
the Cosmological Gas Theory furnishes no starting-point at
all in explanation of the first impulse which caused the
rotary motion in the gas-filled universe. In seeking for
such an impulse, we are involuntarily led to the mistaken
questioning about a " first beginning." We can as little
imagine a first beginning of the eternal phenomena of the
motion of the universe as of its final end.

The universe is unlimited and immeasurable in both
space and time. It is eternal, and it is infinite. Nor can
we imagine a beginning or end to the uninterrupted and
eternal motion in which all particles of the universe are
always engaged. The great laws of the conservation of
force 88 and the conservation of matter, the foundations of
our whole conception of nature, admit of no other supposi-
tion. The universe, as far as it is cognizable to human
capability, appears as a connected chain of material pheno-

THE FIRST OEUST OF THE EARTH. 399

mena of motion, necessitating a continual change of forms.
Every form, as the temporary result of a multiplicity of
phenomena of motion, is as such perishable, and of limited
duration. But, in the continual change of forms, matter
and the motion inseparable from it remain eternal and
indestructible.

Now, although Kant's Cosmological Gas Theory is not
able to explain the development of motion in the whole
universe in a satisfactory manner, beyond that gaseous
state of chaos, and although many other weighty considera-
tions may be brought forward against it, especially by
chemistry and geology, yet we must on the whole acknow-
ledge its great merit, inasmuch as it admirably explains, by
due consideration of development, the whole structure of all
that is accessible to our observation, that is, the " anatomy "
of the solar systems, and especially of our planetary system.
It may be that this development was altogether different
from what Kant supposes, and our earth may have arisen
by the aggregation of numberless small meteorides, scattered
in space ; and some theory of the kind has been brought
forward by A. von Radenhausen, the ingenious author of
the admirable works "Isis" and "Osiris." But in my
opinion these and other similar cosmogonies present even
greater difficulties than that of Kant, but hitherto no one
has as yet been able to establish any other theory of
development, or to offer one in the place of Kant's cosmogony.
After this general glance at the monistic cosmogony, or
the non-miraculous history of the development of the
universe, let us now return to a minute fraction of it, to
our mother earth, which we left as a ball flattened at both
poles and in a fiery liquid state, its surface having condensed

4<X> THE HISTOEY OF CREATION'.

by becoming cooled into a very thin firm crust. The crust,
on first cooling, must have covered the whole surface of the
terrestrial sphere as a continuous smooth and thin shell.
But soon it must have become uneven and hummocky ; for
since, during the continued cooling, the fiery fluid nucleus
became more and more condensed and contracted, and con-
sequently the diameter of the earth diminished, the thin
cold crust, which could not closely follow the softer nuclear
mass, must have fallen in, in many places. An empty
space would have arisen between the two, had not the
pressure of the outer atmosphere forced down the fragile
crust towards the interior, breaking it in so doing. Other
unevennesses probably arose from the fact that, in different
parts, the cooled crust during the process of refrigeration
also contracted, and thus became fissured with cracks and
rents. The fiery fluid nucleus flowed up to the external
surface through these cracks, and again became cooled and
stiff. Thus, even at an early period there arose many
elevations and depressions, which were the first foundations
of mountains and valleys.

After the temperature of the cooled terrestrial ball had
fallen to a certain degree, a very important new process
was effected, namely, the first origin of water. Water had
until then existed only in the form of steam in the atmo-
sphere surrounding the globe. The water could evidently
not condense into a state of fluid drops until the temperature
of the atmosphere had considerably decreased. Now, then,
there began a further transformation of the earth's crust by
the force of water. It continually fell in the form of rain,
and in that form washed down the elevations of the earth's
crust, filling the depressions with the mud carried along,

SPONTANEOUS GENERATION. 401

and, by depositing it in layers, it caused the extremely
important nep tunic transformations of the earth's crust,
which have continued since then uninterruptedly, and
which in our next chapter we shall examine a little more
closely.

It was not till the earth's crust had so far cooled that the
water had condensed into a fluid form, it was not till the
hitherto dry crust of the earth had for the first time become
covered with liquid water, that the origin of the first
organisms could take place. For all animals and all plants
— in fact, all organisms — consist in great measure of fluid
water, which combines in a peculiar manner with other sub-
stances, and brings them into a semi-fluid state of aggrega-
tion. We can therefore, from these general outlines of the
inorganic history of the earth's crust, deduce the important
fact, that at a certain definite time life had its beginning
on earth, and that terrestrial organisms did not exist from
eternity, but at a certain period came into existence for the
first time.

Now, how are we to conceive of this origin of the first
organisms ? This is the point at which most naturalists,
even at the present day, are inclined to give up the attempt
at natural explanation, and take refuge in the miracle of an
inconceivable creation. In doing so, as has already been
remarked, they quit the domain of scientific knowledge,
and renounce all further insight into the eternal laws which
have determined nature's history. But before despondingly
taking such a step, and before we despair of the possibility
of any knowledge of this important process, we may at
least make an attempt to understand it. Let us see if in
reality the origin of a first organism out of inorganic matter,

vol. 1. 2d

402 THE HISTORY OP CREATION.

the origin of a living body out of lifeless matter, is so
utterly inconceivable and beyond all experience. In one
word, let us examine the question of spontaneous generation,
or archigony. In so doing, it is above all things necessary
to form a clear idea of the principal properties of the two
chief groups of natural bodies, the so-called inanimate or
inorganic, and the animate or organic bodies, and then
establish what is common to, and what are the differences
between, the two groups. It is desirable to go somewhat
carefully into the comparison of organisms and anorgana,
since it is commonly very much neglected, although it is
necessary for a right understanding of nature from the
monistic point of view. It will be most advantageous here
to look separately at the three fundamental properties of
every natural body ; these are matter, form, and force. Let
us begin with matter.

By chemistry we have succeeded in analyzing all bodies
known to us into a small number of elements or simple
substances, which cannot be further divided — for example,
carbon, oxygen, nitrogen, sulphur, and the different metals :
potassium, sodium, iron, gold, etc. At present we know
about seventy such elements or simple substances. The
majority of them are unimportant and rare ; the minority
only are widely distributed, and compose not only most of
the anorgana, but also all organisms. If we compare those
elements which constitute the body of organisms with those
which are met with in anorgana, we have first to note the
highly important fact that in animal and vegetable bodies
no element occurs but what can be found outside of them
in inanimate nature. There are no special organic elements
or simple organic substances.

OKGANA AND NON-ORGANA. 403

It may be briefly mentioned here as highly probable that
all of these so-called " elements" are only different forms of
combination of two different primary elements — matter
and ether ; the matter-atoms are endowed with attraction,
the ether-atoms with repulsion. The differences between
our present " elements " probably consist merely in the
matter-atoms being different in number and arrangement,
or by their being separated in some different manner by
the ether-atoms. The group-relationship between the
elements makes this supposition appear very likely, even
though our imperfect chemical knowledge has not yet been
able to demonstrate this experimentally.

The chemical and physical differences existing between
organisms and anorgana, consequently, do not lie in their
material foundation; they do not arise from the different
nature of the elements composing them, but from the
different manner in which the latter are united by chemical
combination. This different manner of combination gives
rise to certain physical peculiarities, especially in density
of substance, which at first sight seems to constitute a deep
chasm between the two groups of bodies. Inorganic or
inanimate natural bodies, such as crystals and the amorphous
rocks, are in a state of density which we call the firm or
solid state, and which we oppose to the liquid state of water
and to the gaseous state of air. It is familiar to every one
that these three different degrees of density, or states of
aggregation of anorgana, are by no means peculiar to the
different elements, but are the results of a certain degree of
temperature. Every inorganic solid body, by increase of
temperature, can be reduced to the liquid or melted state,
and, by further heat, to the gaseous or elastic state. In the

404 THE HISTORY OF CEBATIONl

same way most gaseous bodies, by a proper decrease of
temperature, can first be converted into a liquid state, and
further, into a solid state of density.

In opposition to these three states of density of anorgana,
the living body of all organisms — animals as well as plants
- — is in an altogether peculiar fourth state of aggregation.
It is neither solid like stone, nor liquid like water, but pre-
sents rather a medium between these two states, which may
therefore be designated as the firm-fluid or swollen state of
aggregation (viscid). In all living bodies, without exception,
there is a certain quantity of water combined in a peculiar
way with solid matter, and owing to this characteristic
combination of water with solid matter we have that
soft state of aggregation, neither solid nor liquid, which
is of great importance in the mechanical explanation of
the phenomena of life. Its cause lies essentially in the
physical and chemical properties of a simple, indivisible,
elementary substance, namely, carbon.

Of all elements, carbon is to us by far the most important
and interesting, because this simple substance plays the
largest part in all animal and vegetable bodies known to
us. It is that element which, by its peculiar tendency to
form complicated combinations with the other elements,
produces the greatest variety of chemical compounds, and
among them the forms and living substance of animal and
vegetable bodies. Carbon is especially distinguished by
the fact that it can unite with the other elements in
infinitely manifold relations of number and weight. By the
combination of carbon with three other elements, with
oxygen, hydrogen, and nitrogen (to which generally sulphur,
and frequently, also, phosphorus is added), there arise those

PEQTOPIiASM, THE SEAT OF LIFE. 405

exceedingly important compounds which we have become
acquainted with as the first and most indispensable
substratum of all vital phenomena, the albuminous combina-
tions, or albuminous bodies (protean matter). Of these,
again, the most important are the plasson-body or plasma
combinations (karyoplasm and protoplasm).

We have before this (p. 191) become acquainted with the
simplest of all species of organisms in the Monera, whose
entire bodies when completely developed consist of nothing
but a bit of plasson, or a semi-fluid albuminous lump of
plasma. These simplest of organisms are of the utmost im-
portance for the theory of the first origin of life. But most
other organisms, also, at a certain period of their existence —
at least, in the first period of their life — in the shape of egg-
cells or germ-cells, are essentially nothing but simple little
lumps of such albuminous formative matter, known as cell-
slime or protoplasma. They then differ from the Monera
only by the fact that in the interior of the albuminous
corpuscle the cell-kernel or nucleus has separated itself
from the surrounding cell-substance (cyto-plasma). As we
have already pointed out, the cells, with their simple
attributes, are so many citizens, who by co-operation and
differentiation build up the body of even the most perfect
organism; this being, as it were, a cell republic. The
fully developed form and the vital phenomena of such an
organism are determined solely, by the activities of these
small albuminous plastids.

It may be considered as one of the greatest triumphs of
recent biology, especially of the theory of tissues, that we
are now able to trace the wonder of the phenomena of life
to these substances, and that we can demonstrate the

4Q6 the history of creation.

infinitely manifold and complicated physical and chemical
properties of the albuminous bodies to be the real cause of
organic or vital phenomena. All the different forms of
organisms are simply and directly the result of the combi-
nation of the different forms of cells. The infinitely mani-
fold varieties of form, size, and combination of the cells
have arisen only gradually by the division of labour, and
by form-separation of the plastidules or mi-cells ; by the
molecular selection of those simple homogeneous corpuscles
of plasson, which originally alone formed the body of the
plastids. From this it follows of necessity that the funda-
mental phenomena of life — nutrition and generation — in
their highest manifestations, as well as in their simplest
expressions, must also be traced to the material nature of
that albuminous formative substance the plasson. The
other vital activities are gradually evolved from these two.
Thus, then, the general explanation of life is now no more
difficult to us than the explanation of the physical properties
of inorganic bodies. All vital phenomena and formative
processes of organisms are as directly dependent upon the
chemical composition and the physical forces of organic
matter as the vital phenomena of inorganic crystals — that
is, the process of their growth and their specific formation
are the direct results of their chemical composition and of
their physical condition. The ultimate causes, it is true,
remain in both cases concealed from us. When gold and
copper crystallize in a cubical, bismuth and antimony in a
hexagonal, iodine and sulphur in a rhombic form of crystal,
the occurrence is in reality neither more nor less mysterious
to us than is .every elementary process of organic formation,
every self-formation of the organic cell. In this respect we

THE MONERA. 407

can no longer draw a fundamental distinction between
organisms and anorgana, a distinction of which, formerly,
naturalists were generally convinced.

Let us, secondly, examine the agreements and differences
which are presented to us in the formation of organic and
inorganic natural bodies. Formerly the simple structure of
the latter and the composite structure of the former were
looked upon as the principal distinction. The body of all
organisms was supposed to consist of dissimilar or hetero-
geneous parts, of instruments or organs which worked
together for the purposes of life. On the other hand, the
most perfect anorgana, that is to say, crystals, were supposed
to consist entirely of homogeneous matter. This distinction
appears very essential. But it loses all importance through
the fact that twenty -five years ago we became acquainted
with the exceedingly remarkable and important Monera. 15
The whole body of these most simple of all organisms — a
semi-fluid, formless, and simple lump of plasson — consists,
in fact, of only a single chemical combination, and is as
perfectly simple in its structure as any crystal, which con-
sists of a single inorganic combination, for example, of a
metallic salt or of a silicate of the earths and alkalies. Of
course we assume that even the homogeneous plasma of the
simplest Monera has a very complicated molecular structure ;
however, this is not demonstrable either anatomically or
microscopically ; and besides, the same must be assumed in
the case of many crystals.

As naturalists believed in differences in the inner struc-
ture or composition, so they supposed themselves able to
find complete differences in the external forms of organisms
and anorgana, especially in the mathematically determinable

408 THE HISTORY OF CREATION.

crystalline forms of the latter. Certainly crystallization is
pre-eminently a quality of the so-called anorgana. Crystals
are limited by plane surfaces, which meet in straight lines
and at certain measurable angles. Animal and vegetable
forms, on the contrary, seem at first sight to admit of no
such geometrical determination. They are for the most part
limited by curved surfaces and crooked lines, which meet
at variable angles. But in recent times we have become
acquainted, among Radiolaria and among many other
Protista, with a large number of lower organisms, whose
body, in the same way as crystals, may be traced to a
matnematically determinable fundamental form, and whose
form in its whole, as well as in its parts, is bounded by
definite geometrically determinable planes and angles. In
my general doctrine of Fundamental Forms, or Promor-
phology, I have given detailed proofs of this, and at the
same time established a general system of forms, the ideal
stereometrical type-forms, which explain the real forms of
inorganic crystals, as well as of organic individuals (" Gen.
Morph." i. 375-574). Moreover, there are also perfectly
amorphous organisms, like the Monera, Amoeba, etc., which
change their forms every moment, and in which we are as
little able to point out a definite fundamental form as in
the case of the shapeless or amorphous anorgana, such as
non-crystallized stones, deposits, etc. We are consequently
unable to find any essential difference in the external forms
or the inner structure of anorgana and organisms.

Thirdly, let us turn to the forces or the 'phenomena of
motion of these two different groups of bodies. Here we
meet with the greatest difficulties. The vital phenomena;
known as a rule only in the highly developed organisms,

THE VITAL FOEOE. 409

in the more perfect animals and plants, seem there so
mysterious, so wonderful, so peculiar, that most persons are
decidedly of opinion that in inorganic nature there occurs
nothing at all similar, or in the least degree comparable to
them. Organisms are for this very reason called animate,
and the anorgana, inanimate natural bodies. Hence, even
so late as the commencement of the present century, the
science which investigates the phenomena of life, namely,
physiology, retained the erroneous idea that the physical
and chemical properties of matter were -not sufficient for
explaining these phenomena. Nowadaj r s, this idea may
be regarded as having been completely refuted. In exact
physiology, at least, it has now no place. It now never
occurs to a physiologist to consider any of the vital phenomena
as the result of a mysterious vital force, of an active power
working for a definite purpose, standing outside of matter,
and, so to speak, taking only the physico-chemical forces
into its service. Modern physiology has arrived at the
strictly monistic conviction that all of the vital phenomena,
and, above all, the two fundamental phenomena of nutrition
and propagation, are purely physico-chemical processes, and
directly dependent on the material nature of the organism,
just as all the physical and chemical qualities of every
crystal are determined solely by its material composition.
Now, as the elementary substance which determines the
peculiar material composition of organisms is carbon, We
must ultimately reduce all vital phenomena, and, above all,
the two fundamental phenomena of nutrition and propaga-
tion, to the properties of the carbon. The peculiar chemico-
physical properties, and especially the semi-fluid state of
aggregation, and the easy decomposability of the exceedingly

4IO THE HISTORY OF CREATION.

composite albuminous combinations of carbon, are the
mechanical causes of those peculiar phenomena of motion
which distinguish organisms from anorgana, and which
in a narrow sense are usually called " life."

In order to understand this " carbon theory" which I have
established in detail in the second book of my " General
Morphology," it is necessary, above all things, closely to
examine those phenomena of motion which are common to
both groups of natural bodies. First among them is the
process of growth. If we cause any inorganic solution of
salt slowly to evaporate, crystals are formed in it, which
slowly increase in size during the continued evaporation of
the water. This process of growth arises from the- fact
that new particles continually pass over from the fluid state
of aggregation into the solid, and, according to certain laws,
deposit themselves upon the firm kernel of the crystal
already formed. From such an apposition of particles arise
the mathematically definite crystalline shapes. In like
manner the growth of organisms takes place by the accession
of new particles. The only difference is that in the growth
of organisms, in consequence of their semi-fluid state of
aggregation, the newly added particles penetrate into the
interior of the organism (inter-susception), whereas anor-
gana receive homogeneous matter from without only by
apposition or an addition of new particles to the surface.
This important difference of growth by inter-susception
and by apposition is obviously only the necessary and
direct result of the different conditions of density or state
of aggregation in organisms and anorgana.

Unfortunately I cannot here follow in detail the various
exceedingly interesting parallels and analogies which occur

ADAPTATION IN CRYSTALS. 41 1

between the formation of the most perfect anorgana, the
crystals, and the formation of the simplest organisms, the
Monera and their next kindred forms. For this I must
refer to a minute comparison of organisms and anorgana,
which I have carried out in the fifth chapter of my " General
Morphology" ("Gen. Morph." i. 111-160). I have there
shown in detail that there exist no complete differences
between organic and inorganic natural bodies, neither in
respect to form and structure, nor in respect to matter and
force ; and that the actually existing differences are depen-
dent upon the peculiar nature of the carbon ; and that there
exists no insurmountable chasm between organic and
inorganic nature. We can perceive this most important
fact very clearly if we examine and compare the origin of
the forms in crystals and in the simplest organic individuals.
In the formation of crystal individuals, two different counter-
acting formative tendencies come into operation. The inner
constructive force, or the inner formative tendency, which
corresponds to the Heredity of organisms, in the case of the
crystal is the direct result of its material constitution or of
its chemical composition. The form of the crystal, so far as
it is determined by this inner original formative tendency,
is the result of the specific and definite way in which the
smallest particles of the crystallizing matter unite together
in different directions according to law. That independent
inner formative force, which is directly inherent in the
matter itself, is directly counteracted by a second formative
force. The external constructive force, or the external
formative tendency, may be called Adaptation in crystals as
well as in organisms. Every crystal individual during its
formation, like every organic individual, must submit and

412 THE H1ST0KY OF CREATION.

adapt itself to the surrounding influences and conditions
of existence of the outer world. In fact, the form and size
of every crystal is dependent upon its whole surroundings ;
for example, upon the vessel in which the crystallization
takes place, upon the temperature and the pressure of the
air under which the crystal is formed, upon the presence or
absence of heterogeneous bodies, etc. Consequently, the
form of every single crystal, like the form of every single
organism, is the result of the interaction of two opposing
factors — the inner formative tendency, which is determined
by the chemical constitution of the matter itself, and of the
external formative tendency, which is dependent upon the
influence of surrounding matter. Both these constructive
forces interact similarly also in the organism, and, just as in
the crystal, are of a purely mechanical nature and directly
inherent in the substance of the body. If we designate the
growth and the formation of organisms as a process of life,
we may with equal reason apply the same term to the de-
veloping crystal. The teleologieal conception of nature,
which looks upon organisms as machines of creation arranged
for a definite purpose, must logically acknowledge the same
also in regard to the forms of crystals. The differences
which exist between the simplest organic individuals and
inorganic crystals are determined by the solid state of
aggregation of the latter, and by the semi-fluid state of the
former. Beyond that the causes producing form are exactly
the same in both. This conviction forces itself upon us
most clearly, if we compare the exceedingly remarkable
phenomena of growth, adaptation, and the "correlation of
parts " of developing crystals with the corresponding phe-
nomena of the origin of the simplest organic individuals

SPONTANEOUS GENERATION. 413

(Monera and cells). The analogy between the two is so great
that, in reality, no accurate boundary can be drawn. In
my " General Morphology " I have quoted in support of this
a number of striking facts ("Gen. Morph." i. 146, 156, 158).

If we vividly picture to ourselves this "unity of
organic and inorganic nature" this essential agreement of
organisms and anorgana in matter, form, and force, and if
we bear in mind that we are not able to establish any
one fundamental distinction between these two groups of
bodies (as was formerly generally assumed), then the ques-
tion of spontaneous generation will lose a great deal of the
difficulty which at first seems to surround it. Then the
development of the first organism out of inorganic matter
will appear a much more easily conceivable and intelligible
process than has hitherto been the case, while an artificial
absolute barrier between organic or animate, and inorganic
or inanimate nature was maintained.

In the question of spontaneous generation, or archigony ',
which we can now answer more definitely, it must be
borne in mind that by this conception we understand
generally the non-parental generation of an organic indi-
vidual, the origin of an organism independent of a parental
or producing organism. It is in this sense that on a
former occasion I mentioned spontaneous generation (archi-
gony) as opposed to parental generation or propagation
(tocogony). In the latter case the organic individual arises
by a greater or less portion of an already existing organism
separating itself and growing independently ("Gen. Morph."
ii. 32).

In spontaneous generation, which is often also called
original generation (generatio spontanea, sequivoca, primaria,

414 THE HISTOKY OF CEEATION.

etc.), we must first distinguish two essentially different
kinds, namely, autogeny and plasmogeny. By autogeny
we understand the origin of a most simple organic indi-
vidual in an inorganic formative fluid, that is, in a
fluid which contains the fundamental substances for the
composition of the organism dissolved in simple and loose
combinations (for example, carbonic acid, ammonia, binary
salts, etc.). On the other hand, we call spontaneous genera-
tion plasmogeny when the organism arises in an organic
formative fluid, that is, in a fluid which contains those
requisite fundamental substances dissolved in the form of
complicated and fluid combinations of carbon (for example,
albumen, fat, hydrate of carbon, etc.) (" Gen. Morph." i. 174 ;
ii. 33).

Neither the process of autogeny, nor that of plasmogeny,
has yet been directly observed with perfect certainty.
In early, and also in more recent times, numerous and
interesting experiments have been made as to the possibility
or reality of spontaneous generation. Almost all these
experiments refer not to autogeny, but to plasmogeny, to the
origin of an organism out of already formed organic matter.
It is evident, however, that this latter process is only of
subordinate interest for our history of creation. It is much
more important for us to solve the question, " Is there such
a thing as autogeny ? Is it possible that an organism can
arise, not out of pre-existing organic, but out of purely inor-
ganic, matter?" Hence we can quietly lay aside all the
numerous experiments which refer only to plasmogeny,
which have been carried on very zealously during the last
ten years, and which for the most part have had a negative
result. For even supposing that the reality of plasmogeny

PEIMiEVAL CONDITIONS DIFFEKED. 415

were strictly proved, still autogeny would not be explained
by it.

The experiments on autogeny have likewise as yet
furnished no certain and positive result. Yet we must
at the outset most distinctly protest against the notion
that these experiments have proved the impossibility of
spontaneous generation in general. Most naturalists who
have endeavoured to decide this question experimentally,
and who, after having employed all possible precautionary
measures, under well-ascertained conditions, have seen no
organisms come into being, have straightway made the
assertion, on the ground of these negative results : " That it
is altogether impossible for organisms to come into existence
by themselves without parental generation." This hasty
and inconsiderate assertion they have supported by the
negative results of their experiments, which, after all, could
prove nothing except that, under these or those highly
artificial circumstances created by the experimenters them-
selves, no organism was developed. From these experi-
ments, which have been for the most part made under the
most unnatural conditions, and in a highly artificial
manner, we can by no means draw the conclusion that
spontaneous generation in general is impossible. The
impossibility of such a process can, in fact, never be proved.
For how can we know that in remote primaeval times there
did not exist conditions quite different from those at
present obtaining, and which may have rendered spon-
taneous generation possible ? Indeed, we can even posi-
tively and with full assurance maintain that the general
conditions of life in primaeval times must have been entirely
different from those of the present time. Think only of the

416 THE HISTORY OF CREATION.

fact that the enormous masses of carbon which we now
find deposited in the primary coal mountains were first
reduced to a solid form by the action of vegetable life, and
are the compressed and condensed remains of innumerable
vegetable substances, which have accumulated in the
course of many millions of years. But at the time when,
after the origin of water in a liquid state on the cooled
crust of the earth, organisms were first formed by
spontaneous generation, those immeasurable quantities of
carbon existed in a totally different form, probably for the
most part dispersed in the atmosphere in the shape of
carbonic acid. The whole composition of the atmosphere
was therefore extremely different from the present.
Further, as may be inferred upon chemical, physical, and
geological grounds, the density and the electrical conditions
of the atmosphere were quite different. In like manner the
chemical and physical nature of the primaeval ocean, which
then continously covered the whole surface of the earth as
an uninterrupted watery sheet, was quite peculiar. The
temperature, the density, the amount of salt, etc., must have
been very different from those of the present ocean. In
any case, therefore, even if we do not know anything more
about it, there remains to us the supposition, which can at
least not be disputed, that at that time, under conditions
quite different from those of to-day, a spontaneous genera-
tion, which now is perhaps no longer possible, may have
taken place.

But it is necessary to add here that, by the recent pro-
gress of chemistry and physiology, the mysterious and
miraculous character which at first seems to belong to this
much disputed and yet inevitable process of spontaneous

THE MONEKA AND ARCHIGONY. 417

generation, has been to a great extent, or almost entirely,
destroyed. Not sixty years ago, all chemists maintained that
we were unable to produce artificially in our laboratories
any complicated combination of carbon, or so-called " organic
combination." The mystic "vital force" alone was sup-
posed to be able to produce these combinations. When,
therefore, in 1828, Wohler, in Gottingen, for the first time
refuted this dogma, and exhibited pure " organic " urea, ob-
tained in an artificial manner from a purely inorganic body
(cyanate of ammonium), it caused the greatest surprise and
astonishment. In more recent times, by the progress of
synthetic chemistry, we have succeeded in producing in our
laboratories a great variety of similar " organic " combi-
nations of carbon, by purely artificial means — for example,
alcohol, acetic acid, formic acid. Indeed, many exceed-
ingly complicated combinations of carbon are now arti-
ficially produced, so that there is every likelihood, sooner
or later, of our producing artificially the most complicated,
and at the same time the most important of all, namely, the
albuminous combinations, or plasson-bodies. By the con-
sideration of this probability, the deep chasm which was
formerly and generally believed to exist between organic
and inorganic bodies is almost or entirely removed, and
the way is paved for the conception of spontaneous
generation.

Of still greater, nay, the very greatest importance to the
hypothesis of spontaneous generation are, finally, the ex-
ceedingly remarkable Monera, those creatures which we
have already so frequently mentioned, and which are not
only the simplest of all observed organisms, but even the
simplest of all imaginable organisms. I have already
vol. 1. 2 E

41 8 THE HISTOBY OF CREATION.

described these wonderful "organisms without organs,"
when examining the simplest phenomena of propagation
and inheritance. We already know seven different genera
of these Monera, some of which live in fresh water, others
in the sea (compare above, p. 191; also Plate I. and its
explanation in the Appendix). In a perfectly developed
and freely mobile state, they one and all present us with
nothing but a simple little lump of an albuminous combina-
tion of carbon. The individual genera and species differ
only a little in the manner of propagation and development
and in the way of taking nourishment. Through the dis-
covery of these organisms, which are of the utmost impor-
tance, the supposition of a spontaneous generation loses most
of its difficulties. For as all trace of organization — all dis-
tinction of heterogeneous parts — is still wanting in them,
and as all the vital phenomena are performed by one and
the same homogeneous and formless matter, we can easily
imagine their origin by spontaneous generation. If this
happens through plasmogeny, and if plasma capable of life
already exists, it then only needs to individualize itself in
the same way as the mother liquor of crystals individualizes
itself in crystallization. If, on the other hand, the spon-
taneous generation of the Monera takes place by true
aviogeny, then it is further requisite that that plasson
capable of life, that primaeval mucus, should be formed out
of simpler combinations of carbon. As we are now able
artificially to produce, in our laboratories, combinations of
carbon similar to this in the complexity of their constitution,
there is absolutely no reason for supposing that there are
not conditions in free nature also, in which such combina-
tions could take place. Formerly, when the doctrine of

THE MONERON BECOMES A CELL. 419

spontaneous generation was advocated, it failed at once to
obtain adherents on account of the composite structure of
the simplest organisms then known. It is only since we
have discovered the exceedingly important Monera, only
since we have become acquainted in them with organisms
not in any way built up of distinct organs, but which
consist solely of a single chemical combination, and yet
grow, nourish, and propagate themselves, that this great
difficulty has been removed, and the hypothesis of spon-
taneous generation has gained a degree of probability which
entitles it to fill up the gap existing between Kant's
cosmogony and Lamarck's Theory of Descent.

Only such homogeneous organisms as are yet not differen-
tiated, and are similar to inorganic crystals in being homo-
geneously composed of one single substance, could arise by
spontaneous generation, and could become the primaeval
parents of all other organisms. In their further develop-
ment we have pointed out that the most important process
is the formation of a kernel or nucleus in the simple little
lump of plasson. We can conceive this to take place in a
purely physical manner, by the condensation of the inner-
most central part of the albumen. The more solid central
mass, which at first gradually shaded off into the peripheral
plasma, becomes sharply separated from it, and thus forms
an independent, round, albuminous corpuscle, the kernel ;
and by this process the Moneron becomes a cell. Now, it
must have become evident from our previous chapters, that
the further development of all other organisms out of such
a cell presents no difficulty, for every animal and every
plant, in the beginning of its individual life, is a simple cell.
Man, as well as every other animal, is at first nothing but

420 THE HISTORY OF CREATION.

a simple egg-cell, a simple lump of mucus, containing a
kernel (p. 297, Fig. 5).

In the same way as the kernel of the organic cell arose
in the interior or central mass of the originally homogeneous
lump of plasma, by separation, so, too, the first cell-membrane
was formed on its surface. This simple, hut most important
process, as has already been remarked, can likewise be ex-
plained in a purely physical manner, either as a chemical
deposit, or as a physical condensation in the uppermost
stratum of the mass, or as a secretion. One of the first
processes of adaptation effected by the Moneron originating
by spontaneous generation must have been the condensation
of an external crust, which as a protecting covering shut in
the softer interior from the hostile influences of the outer
world. As soon as, by condensation of the homogeneous
Moneron, a cell-kernel arose in the interior and a membrane
arose on the surface, all the fundamental parts of the unit
were furnished, out of which, by infinitely manifold repeti-
tion and combination, as attested by actual observation, the
body of higher organisms is constructed.

As has already been mentioned, our whole understanding
of an organism rests upon the cell theory established in
1838 by Schleiden and Schwann. According to it, every
organism is either a simple cell or a cell-community, a
republic of closely connected cells. All the forms and vital
phenomena of every organism are the collective result of
the forms and vital phenomena of all the single cells of
which it is composed. By the recent progress of the cell
theory it has become necessary to give the elementary
organisms, that is, the " organic " individuals of the first
order, which are usually designated as cells, the more

FOUR ORDERS OP PLASTIDS. 42 1

general and more suitable name of form-units, or plastids.
Among these form-units we distinguish two main groups,
namely, the cytods and the genuine cells. The cytods are,
like the Monera, pieces of plasma without a kernel (p. 190,
Fig. 1). Cells, on the other hand, are pieees of plasma con-
taining a kernel or nucleus (p. 193, Fig. 2). Each of these
two main groups of plastids is again divided into two sub-
ordinate groups, according as they possess or do not possess
an external covering (skin, shell, or membrane). We may
accordingly distinguish the following four grades or species
of plastids, namely : 1. Simple cytods (p. 191, Fig. 1 A) ;
2. Encased cytods ; 3. Simple cells (p. 193, Fig. 2 B) ; 4. En-
cased cells (p. 193, Fig. 2 A). (" Gen. Morph." i. 269-289.)
Concerning the relation of these four forms of plastids to
spontaneous generation, the following is the most probable :
1. The simple cytods (Gymnocytoda), naked particles of
plasma without kernel, like the still living Monera, are the
only plastids which directly come into existence by spon-
taneous generation. 2. The enclosed cytods (Lepocytoda),
particles of plasma without kernel, which are surrounded
by a covering (membrane or shell), arose out of the simple
cytods either by the condensation of the outer layers of
plasma or by the secretion of a covering. 8. The simple
cells (Gymnocyta), or naked cells, particles of plasma with
kernel, but without covering, arose out of the simple cytods
by the condensation of the innermost particles of plasma
into a kernel or nucleus, by differentiation of a central
kernel and peripheral cell-substance. 4. The enclosed cells
(Lepocyta), or testaceous cells, particles of plasma with
kernel and an outer covering (membrane or shell), arose
either out of the enclosed cytods by the formation of a

422 THE HISTOEY OF CKEATIOST.

kernel, or out of the simple cells by the formation of a
membrane. All the other forms of plastids or form-units
met with, besides these, have- only subsequently arisen out
of these four fundamental forms by natural selection, by
descent with adaptation, by differentiation and transforma-
tion.

By this theory of plastids, by deducing all the different
forms of plastids, and hence, also, all organisms composed
of them, from the Monera, we obtain a simple and natural
connection in the whole series of the development of nature.
The origin of the first Monera by spontaneous generation
appears to us as a simple and necessary event in the process
of the development of the earth. We admit that this
process, as long as it is not directly observed or repeated
by experiment, remains a pure hypothesis. But I must
again say that this hypothesis is indispensable for the con-
sistent completion of the non-miraculous history of creation,
that it has absolutely nothing forced or miraculous about
it, and that certainly it can never be positively refuted. It
must also be taken into consideration that the process of
spontaneous generation, even if it still took place daily and
hourly, would in any case be exceedingly difficult to observe
and establish with absolute certainty as such. This is also
the opinion of Naegeli, the ingenious investigator, and he,
in his admirable chapter on Spontaneous Generation, main-
tains that " to deny spontaneous generation is to proclaim
miracles."

END OF VOL. I.

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